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+/******
+* name: arkenfox user.js
+* date: 25 April 2021
+* version 89-alpha
+* url: https://github.com/arkenfox/user.js
+* license: MIT: https://github.com/arkenfox/user.js/blob/master/LICENSE.txt
+
+* README:
+
+  1. Consider using Tor Browser if it meets your needs or fits your threat model better
+       * https://www.torproject.org/about/torusers.html.en
+  2. Required reading: Overview, Backing Up, Implementing, and Maintenance entries
+       * https://github.com/arkenfox/user.js/wiki
+  3. If you skipped step 2, return to step 2
+  4. Make changes
+       * There are often trade-offs and conflicts between security vs privacy vs anti-fingerprinting
+         and these need to be balanced against functionality & convenience & breakage
+       * Some site breakage and unintended consequences will happen. Everyone's experience will differ
+         e.g. some user data is erased on close (section 2800), change this to suit your needs
+       * While not 100% definitive, search for "[SETUP" tags
+         e.g. third party images/videos not loading on some sites? check 1603
+       * Take the wiki link in step 2 and read the Troubleshooting entry
+  5. Some tag info
+       [SETUP-SECURITY] it's one item, read it
+            [SETUP-WEB] can cause some websites to break
+         [SETUP-CHROME] changes how Firefox itself behaves (i.e. not directly website related)
+           [SETUP-PERF] may impact performance
+              [WARNING] used sparingly, heed them
+  6. Override Recipes: https://github.com/arkenfox/user.js/issues/1080
+
+* RELEASES: https://github.com/arkenfox/user.js/releases
+
+  * It is best to use the arkenfox release that is optimized for and matches your Firefox version
+  * EVERYONE: each release
+    - run prefsCleaner or reset deprecated prefs (9999s) and prefs made redundant by RPF (4600s)
+    - re-enable section 4600 if you don't use RFP
+    ESR78
+    - If you are not using arkenfox v78... (not a definitive list)
+      - 1244: HTTPS-Only mode is enabled
+      - 1401: document fonts is inactive as it is now covered by RFP in FF80+
+      - 4600: some prefs may apply even if you use RFP
+      - 9999: switch the appropriate deprecated section(s) back on
+
+* INDEX:
+
+  0100: STARTUP
+  0200: GEOLOCATION / LANGUAGE / LOCALE
+  0300: QUIET FOX
+  0400: BLOCKLISTS / SAFE BROWSING
+  0500: SYSTEM ADD-ONS / EXPERIMENTS
+  0600: BLOCK IMPLICIT OUTBOUND
+  0700: HTTP* / TCP/IP / DNS / PROXY / SOCKS etc
+  0800: LOCATION BAR / SEARCH BAR / SUGGESTIONS / HISTORY / FORMS
+  0900: PASSWORDS
+  1000: CACHE / SESSION (RE)STORE / FAVICONS
+  1200: HTTPS (SSL/TLS / OCSP / CERTS / HPKP / CIPHERS)
+  1400: FONTS
+  1600: HEADERS / REFERERS
+  1700: CONTAINERS
+  1800: PLUGINS
+  2000: MEDIA / CAMERA / MIC
+  2200: WINDOW MEDDLING & LEAKS / POPUPS
+  2300: WEB WORKERS
+  2400: DOM (DOCUMENT OBJECT MODEL) & JAVASCRIPT
+  2500: HARDWARE FINGERPRINTING
+  2600: MISCELLANEOUS
+  2700: PERSISTENT STORAGE
+  2800: SHUTDOWN
+  4000: FPI (FIRST PARTY ISOLATION)
+  4500: RFP (RESIST FINGERPRINTING)
+  4600: RFP ALTERNATIVES
+  4700: RFP ALTERNATIVES (USER AGENT SPOOFING)
+  5000: PERSONAL
+  9999: DEPRECATED / REMOVED / LEGACY / RENAMED
+
+******/
+
+/* START: internal custom pref to test for syntax errors
+ * [NOTE] In FF60+, not all syntax errors cause parsing to abort i.e. reaching the last debug
+ * pref no longer necessarily means that all prefs have been applied. Check the console right
+ * after startup for any warnings/error messages related to non-applied prefs
+ * [1] https://blog.mozilla.org/nnethercote/2018/03/09/a-new-preferences-parser-for-firefox/ ***/
+user_pref("_user.js.parrot", "START: Oh yes, the Norwegian Blue... what's wrong with it?");
+
+/* 0000: disable about:config warning
+ * FF73-86: chrome://global/content/config.xhtml ***/
+user_pref("general.warnOnAboutConfig", false); // XHTML version
+user_pref("browser.aboutConfig.showWarning", false); // HTML version [FF71+]
+
+/*** [SECTION 0100]: STARTUP ***/
+user_pref("_user.js.parrot", "0100 syntax error: the parrot's dead!");
+/* 0101: disable default browser check
+ * [SETTING] General>Startup>Always check if Firefox is your default browser ***/
+user_pref("browser.shell.checkDefaultBrowser", false);
+/* 0102: set startup page [SETUP-CHROME]
+ * 0=blank, 1=home, 2=last visited page, 3=resume previous session
+ * [NOTE] Session Restore is not used in PB mode (0110) and is cleared with history (2803, 2804)
+ * [SETTING] General>Startup>Restore previous session ***/
+user_pref("browser.startup.page", 0);
+/* 0103: set HOME+NEWWINDOW page
+ * about:home=Activity Stream (default, see 0105), custom URL, about:blank
+ * [SETTING] Home>New Windows and Tabs>Homepage and new windows ***/
+user_pref("browser.startup.homepage", "about:blank");
+/* 0104: set NEWTAB page
+ * true=Activity Stream (default, see 0105), false=blank page
+ * [SETTING] Home>New Windows and Tabs>New tabs ***/
+user_pref("browser.newtabpage.enabled", false);
+user_pref("browser.newtab.preload", false);
+/* 0105: disable Activity Stream stuff (AS)
+ * AS is the default homepage/newtab in FF57+, based on metadata and browsing behavior.
+ *    **NOT LISTING ALL OF THESE: USE THE PREFERENCES UI**
+ * [SETTING] Home>Firefox Home Content>...  to show/hide what you want ***/
+/* 0105a: disable Activity Stream telemetry ***/
+user_pref("browser.newtabpage.activity-stream.feeds.telemetry", false);
+user_pref("browser.newtabpage.activity-stream.telemetry", false);
+/* 0105b: disable Activity Stream Snippets
+ * Runs code received from a server (aka Remote Code Execution) and sends information back to a metrics server
+ * [1] https://abouthome-snippets-service.readthedocs.io/ ***/
+user_pref("browser.newtabpage.activity-stream.feeds.snippets", false); // [DEFAULT: false FF89+]
+/* 0105c: disable Activity Stream Top Stories, Pocket-based and/or sponsored content ***/
+user_pref("browser.newtabpage.activity-stream.feeds.section.topstories", false);
+user_pref("browser.newtabpage.activity-stream.section.highlights.includePocket", false);
+user_pref("browser.newtabpage.activity-stream.showSponsored", false);
+user_pref("browser.newtabpage.activity-stream.feeds.discoverystreamfeed", false); // [FF66+]
+/* 0105e: clear default topsites
+ * [NOTE] This does not block you from adding your own ***/
+user_pref("browser.newtabpage.activity-stream.default.sites", "");
+/* 0110: start Firefox in PB (Private Browsing) mode
+ * [NOTE] In this mode *all* windows are "private windows" and the PB mode icon is not displayed
+ * [WARNING] The P in PB mode is misleading: it means no "persistent" disk storage such as history,
+ * caches, searches, cookies, localStorage, IndexedDB etc (which you can achieve in normal mode).
+ * In fact, PB mode limits or removes the ability to control some of these, and you need to quit
+ * Firefox to clear them. PB is best used as a one off window (File>New Private Window) to provide
+ * a temporary self-contained new session. Close all Private Windows to clear the PB mode session.
+ * [SETTING] Privacy & Security>History>Custom Settings>Always use private browsing mode
+ * [1] https://wiki.mozilla.org/Private_Browsing
+ * [2] https://spreadprivacy.com/is-private-browsing-really-private/ ***/
+   // user_pref("browser.privatebrowsing.autostart", true);
+
+/*** [SECTION 0200]: GEOLOCATION / LANGUAGE / LOCALE ***/
+user_pref("_user.js.parrot", "0200 syntax error: the parrot's definitely deceased!");
+/** GEOLOCATION ***/
+/* 0201: disable Location-Aware Browsing
+ * [NOTE] Best left at default "true", fingerprintable, already behind a prompt (see 0202)
+ * [1] https://www.mozilla.org/firefox/geolocation/ ***/
+   // user_pref("geo.enabled", false);
+/* 0202: set a default permission for Location (see 0201) [FF58+]
+ * 0=always ask (default), 1=allow, 2=block
+ * [NOTE] Best left at default "always ask", fingerprintable via Permissions API
+ * [SETTING] to add site exceptions: Ctrl+I>Permissions>Access Your Location
+ * [SETTING] to manage site exceptions: Options>Privacy & Security>Permissions>Location>Settings ***/
+   // user_pref("permissions.default.geo", 2);
+/* 0203: use Mozilla geolocation service instead of Google when geolocation is enabled [FF74+]
+ * Optionally enable logging to the console (defaults to false) ***/
+user_pref("geo.provider.network.url", "https://location.services.mozilla.com/v1/geolocate?key=%MOZILLA_API_KEY%");
+   // user_pref("geo.provider.network.logging.enabled", true); // [HIDDEN PREF]
+/* 0204: disable using the OS's geolocation service ***/
+user_pref("geo.provider.ms-windows-location", false); // [WINDOWS]
+user_pref("geo.provider.use_corelocation", false); // [MAC]
+user_pref("geo.provider.use_gpsd", false); // [LINUX]
+/* 0207: disable region updates
+ * [1] https://firefox-source-docs.mozilla.org/toolkit/modules/toolkit_modules/Region.html ***/
+user_pref("browser.region.network.url", ""); // [FF78+]
+user_pref("browser.region.update.enabled", false); // [[FF79+]
+/* 0208: set search region
+ * [NOTE] May not be hidden if Firefox has changed your settings due to your region (see 0207) ***/
+   // user_pref("browser.search.region", "US"); // [HIDDEN PREF]
+
+/** LANGUAGE / LOCALE ***/
+/* 0210: set preferred language for displaying web pages
+ * [TEST] https://addons.mozilla.org/about ***/
+user_pref("intl.accept_languages", "en-US, en");
+/* 0211: enforce US English locale regardless of the system locale
+ * [SETUP-WEB] May break some input methods e.g xim/ibus for CJK languages [1]
+ * [1] https://bugzilla.mozilla.org/buglist.cgi?bug_id=867501,1629630 ***/
+user_pref("javascript.use_us_english_locale", true); // [HIDDEN PREF]
+
+/*** [SECTION 0300]: QUIET FOX
+     We only disable the auto-INSTALL of Firefox (app) updates. You still get prompts to update,
+     and it only takes one click. We highly discourage disabling auto-CHECKING for updates.
+
+     Legitimate reasons to disable auto-INSTALLS include hijacked/monetized extensions, time
+     constraints, legacy issues, dev/testing, and fear of breakage/bugs. It is still important
+     to do updates for security reasons, please do so manually if you make changes.
+***/
+user_pref("_user.js.parrot", "0300 syntax error: the parrot's not pinin' for the fjords!");
+/* 0301b: disable auto-CHECKING for extension and theme updates ***/
+   // user_pref("extensions.update.enabled", false);
+/* 0302a: disable auto-INSTALLING Firefox updates [NON-WINDOWS FF65+]
+ * [NOTE] In FF65+ on Windows this SETTING (below) is now stored in a file and the pref was removed
+ * [SETTING] General>Firefox Updates>Check for updates but let you choose to install them ***/
+user_pref("app.update.auto", false);
+/* 0302b: disable auto-INSTALLING extension and theme updates (after the check in 0301b)
+ * [SETTING] about:addons>Extensions>[cog-wheel-icon]>Update Add-ons Automatically (toggle) ***/
+   // user_pref("extensions.update.autoUpdateDefault", false);
+/* 0306: disable extension metadata
+ * used when installing/updating an extension, and in daily background update checks:
+ * when false, extension detail tabs will have no description ***/
+   // user_pref("extensions.getAddons.cache.enabled", false);
+/* 0308: disable search engine updates (e.g. OpenSearch)
+ * [NOTE] This does not affect Mozilla's built-in or Web Extension search engines ***/
+user_pref("browser.search.update", false);
+/* 0320: disable about:addons' Recommendations pane (uses Google Analytics) ***/
+user_pref("extensions.getAddons.showPane", false); // [HIDDEN PREF]
+/* 0321: disable recommendations in about:addons' Extensions and Themes panes [FF68+] ***/
+user_pref("extensions.htmlaboutaddons.recommendations.enabled", false);
+/* 0330: disable telemetry
+ * the pref (.unified) affects the behaviour of the pref (.enabled)
+ * IF unified=false then .enabled controls the telemetry module
+ * IF unified=true then .enabled ONLY controls whether to record extended data
+ * so make sure to have both set as false
+ * [NOTE] FF58+ 'toolkit.telemetry.enabled' is now LOCKED to reflect prerelease
+ * or release builds (true and false respectively) [2]
+ * [1] https://firefox-source-docs.mozilla.org/toolkit/components/telemetry/telemetry/internals/preferences.html
+ * [2] https://medium.com/georg-fritzsche/data-preference-changes-in-firefox-58-2d5df9c428b5 ***/
+user_pref("toolkit.telemetry.unified", false);
+user_pref("toolkit.telemetry.enabled", false); // see [NOTE]
+user_pref("toolkit.telemetry.server", "data:,");
+user_pref("toolkit.telemetry.archive.enabled", false);
+user_pref("toolkit.telemetry.newProfilePing.enabled", false); // [FF55+]
+user_pref("toolkit.telemetry.shutdownPingSender.enabled", false); // [FF55+]
+user_pref("toolkit.telemetry.updatePing.enabled", false); // [FF56+]
+user_pref("toolkit.telemetry.bhrPing.enabled", false); // [FF57+] Background Hang Reporter
+user_pref("toolkit.telemetry.firstShutdownPing.enabled", false); // [FF57+]
+/* 0331: disable Telemetry Coverage
+ * [1] https://blog.mozilla.org/data/2018/08/20/effectively-measuring-search-in-firefox/ ***/
+user_pref("toolkit.telemetry.coverage.opt-out", true); // [HIDDEN PREF]
+user_pref("toolkit.coverage.opt-out", true); // [FF64+] [HIDDEN PREF]
+user_pref("toolkit.coverage.endpoint.base", "");
+/* 0340: disable Health Reports
+ * [SETTING] Privacy & Security>Firefox Data Collection & Use>Allow Firefox to send technical... data ***/
+user_pref("datareporting.healthreport.uploadEnabled", false);
+/* 0341: disable new data submission, master kill switch [FF41+]
+ * If disabled, no policy is shown or upload takes place, ever
+ * [1] https://bugzilla.mozilla.org/1195552 ***/
+user_pref("datareporting.policy.dataSubmissionEnabled", false);
+/* 0342: disable Studies (see 0503)
+ * [SETTING] Privacy & Security>Firefox Data Collection & Use>Allow Firefox to install and run studies ***/
+user_pref("app.shield.optoutstudies.enabled", false);
+/* 0343: disable personalized Extension Recommendations in about:addons and AMO [FF65+]
+ * [NOTE] This pref has no effect when Health Reports (0340) are disabled
+ * [SETTING] Privacy & Security>Firefox Data Collection & Use>Allow Firefox to make personalized extension recommendations
+ * [1] https://support.mozilla.org/kb/personalized-extension-recommendations ***/
+user_pref("browser.discovery.enabled", false);
+/* 0350: disable Crash Reports ***/
+user_pref("breakpad.reportURL", "");
+user_pref("browser.tabs.crashReporting.sendReport", false); // [FF44+]
+   // user_pref("browser.crashReports.unsubmittedCheck.enabled", false); // [FF51+] [DEFAULT: false]
+/* 0351: enforce no submission of backlogged Crash Reports [FF58+]
+ * [SETTING] Privacy & Security>Firefox Data Collection & Use>Allow Firefox to send backlogged crash reports  ***/
+user_pref("browser.crashReports.unsubmittedCheck.autoSubmit2", false); // [DEFAULT: false]
+/* 0390: disable Captive Portal detection
+ * [1] https://www.eff.org/deeplinks/2017/08/how-captive-portals-interfere-wireless-security-and-privacy
+ * [2] https://wiki.mozilla.org/Necko/CaptivePortal ***/
+user_pref("captivedetect.canonicalURL", "");
+user_pref("network.captive-portal-service.enabled", false); // [FF52+]
+/* 0391: disable Network Connectivity checks [FF65+]
+ * [1] https://bugzilla.mozilla.org/1460537 ***/
+user_pref("network.connectivity-service.enabled", false);
+
+/*** [SECTION 0400]: BLOCKLISTS / SAFE BROWSING (SB) ***/
+user_pref("_user.js.parrot", "0400 syntax error: the parrot's passed on!");
+/** BLOCKLISTS ***/
+/* 0401: enforce Firefox blocklist
+ * [NOTE] It includes updates for "revoked certificates"
+ * [1] https://blog.mozilla.org/security/2015/03/03/revoking-intermediate-certificates-introducing-onecrl/ ***/
+user_pref("extensions.blocklist.enabled", true); // [DEFAULT: true]
+
+/** SAFE BROWSING (SB)
+    Safe Browsing has taken many steps to preserve privacy. *IF* required, a full url is never
+    sent to Google, only a PART-hash of the prefix, and this is hidden with noise of other real
+    PART-hashes. Google also swear it is anonymized and only used to flag malicious sites.
+    Firefox also takes measures such as striping out identifying parameters and since SBv4 (FF57+)
+    doesn't even use cookies. (#Turn on browser.safebrowsing.debug to monitor this activity)
+
+    [1] https://feeding.cloud.geek.nz/posts/how-safe-browsing-works-in-firefox/
+    [2] https://wiki.mozilla.org/Security/Safe_Browsing
+    [3] https://support.mozilla.org/en-US/kb/how-does-phishing-and-malware-protection-work
+***/
+/* 0410: disable SB (Safe Browsing)
+ * [WARNING] Do this at your own risk! These are the master switches.
+ * [SETTING] Privacy & Security>Security>... "Block dangerous and deceptive content" ***/
+   // user_pref("browser.safebrowsing.malware.enabled", false);
+   // user_pref("browser.safebrowsing.phishing.enabled", false);
+/* 0411: disable SB checks for downloads (both local lookups + remote)
+ * This is the master switch for the safebrowsing.downloads* prefs (0412, 0413)
+ * [SETTING] Privacy & Security>Security>... "Block dangerous downloads" ***/
+   // user_pref("browser.safebrowsing.downloads.enabled", false);
+/* 0412: disable SB checks for downloads (remote)
+ * To verify the safety of certain executable files, Firefox may submit some information about the
+ * file, including the name, origin, size and a cryptographic hash of the contents, to the Google
+ * Safe Browsing service which helps Firefox determine whether or not the file should be blocked
+ * [SETUP-SECURITY] If you do not understand this, or you want this protection, then override it ***/
+user_pref("browser.safebrowsing.downloads.remote.enabled", false);
+user_pref("browser.safebrowsing.downloads.remote.url", "");
+/* 0413: disable SB checks for unwanted software
+ * [SETTING] Privacy & Security>Security>... "Warn you about unwanted and uncommon software" ***/
+   // user_pref("browser.safebrowsing.downloads.remote.block_potentially_unwanted", false);
+   // user_pref("browser.safebrowsing.downloads.remote.block_uncommon", false);
+/* 0419: disable 'ignore this warning' on SB warnings [FF45+]
+ * If clicked, it bypasses the block for that session. This is a means for admins to enforce SB
+ * [TEST] see github wiki APPENDIX A: Test Sites: Section 5
+ * [1] https://bugzilla.mozilla.org/1226490 ***/
+   // user_pref("browser.safebrowsing.allowOverride", false);
+
+/*** [SECTION 0500]: SYSTEM ADD-ONS / EXPERIMENTS
+     System Add-ons are a method for shipping extensions, considered to be
+     built-in features to Firefox, that are hidden from the about:addons UI.
+     To view your System Add-ons go to about:support, they are listed under "Firefox Features"
+
+     * Portable: "...\App\Firefox64\browser\features\" (or "App\Firefox\etc" for 32bit)
+     * Windows: "...\Program Files\Mozilla\browser\features" (or "Program Files (X86)\etc" for 32bit)
+     * Mac: "...\Applications\Firefox\Contents\Resources\browser\features\"
+            [NOTE] On Mac you can right-click on the application and select "Show Package Contents"
+     * Linux: "/usr/lib/firefox/browser/features" (or similar)
+
+     [1] https://firefox-source-docs.mozilla.org/toolkit/mozapps/extensions/addon-manager/SystemAddons.html
+     [2] https://searchfox.org/mozilla-central/source/browser/extensions
+***/
+user_pref("_user.js.parrot", "0500 syntax error: the parrot's cashed in 'is chips!");
+/* 0503: disable Normandy/Shield [FF60+]
+ * Shield is an telemetry system (including Heartbeat) that can also push and test "recipes"
+ * [1] https://wiki.mozilla.org/Firefox/Shield
+ * [2] https://github.com/mozilla/normandy ***/
+user_pref("app.normandy.enabled", false);
+user_pref("app.normandy.api_url", "");
+/* 0505: disable System Add-on updates ***/
+user_pref("extensions.systemAddon.update.enabled", false); // [FF62+]
+user_pref("extensions.systemAddon.update.url", ""); // [FF44+]
+/* 0506: disable PingCentre telemetry (used in several System Add-ons) [FF57+]
+ * Currently blocked by 'datareporting.healthreport.uploadEnabled' (see 0340) ***/
+user_pref("browser.ping-centre.telemetry", false);
+/* 0515: disable Screenshots ***/
+   // user_pref("extensions.screenshots.disabled", true); // [FF55+]
+/* 0517: disable Form Autofill
+ * [NOTE] Stored data is NOT secure (uses a JSON file)
+ * [NOTE] Heuristics controls Form Autofill on forms without @autocomplete attributes
+ * [SETTING] Privacy & Security>Forms and Autofill>Autofill addresses
+ * [1] https://wiki.mozilla.org/Firefox/Features/Form_Autofill ***/
+user_pref("extensions.formautofill.addresses.enabled", false); // [FF55+]
+user_pref("extensions.formautofill.available", "off"); // [FF56+]
+user_pref("extensions.formautofill.creditCards.available", false); // [FF57+]
+user_pref("extensions.formautofill.creditCards.enabled", false); // [FF56+]
+user_pref("extensions.formautofill.heuristics.enabled", false); // [FF55+]
+/* 0518: enforce disabling of Web Compatibility Reporter [FF56+]
+ * Web Compatibility Reporter adds a "Report Site Issue" button to send data to Mozilla ***/
+user_pref("extensions.webcompat-reporter.enabled", false); // [DEFAULT: false]
+
+/*** [SECTION 0600]: BLOCK IMPLICIT OUTBOUND [not explicitly asked for - e.g. clicked on] ***/
+user_pref("_user.js.parrot", "0600 syntax error: the parrot's no more!");
+/* 0601: disable link prefetching
+ * [1] https://developer.mozilla.org/docs/Web/HTTP/Link_prefetching_FAQ ***/
+user_pref("network.prefetch-next", false);
+/* 0602: disable DNS prefetching
+ * [1] https://developer.mozilla.org/docs/Web/HTTP/Headers/X-DNS-Prefetch-Control ***/
+user_pref("network.dns.disablePrefetch", true);
+   // user_pref("network.dns.disablePrefetchFromHTTPS", true); // [DEFAULT: true]
+/* 0603: disable predictor / prefetching ***/
+user_pref("network.predictor.enabled", false);
+   // user_pref("network.predictor.enable-prefetch", false); // [FF48+] [DEFAULT: false]
+/* 0605: disable link-mouseover opening connection to linked server
+ * [1] https://news.slashdot.org/story/15/08/14/2321202/how-to-quash-firefoxs-silent-requests ***/
+user_pref("network.http.speculative-parallel-limit", 0);
+/* 0606: enforce no "Hyperlink Auditing" (click tracking)
+ * [1] https://www.bleepingcomputer.com/news/software/major-browsers-to-prevent-disabling-of-click-tracking-privacy-risk/ ***/
+   // user_pref("browser.send_pings", false); // [DEFAULT: false]
+
+/*** [SECTION 0700]: HTTP* / TCP/IP / DNS / PROXY / SOCKS etc ***/
+user_pref("_user.js.parrot", "0700 syntax error: the parrot's given up the ghost!");
+/* 0701: disable IPv6
+ * IPv6 can be abused, especially with MAC addresses, and can leak with VPNs. That's even
+ * assuming your ISP and/or router and/or website can handle it. Sites will fall back to IPv4
+ * [STATS] Firefox telemetry (Dec 2020) shows ~8% of all connections are IPv6
+ * [NOTE] This is just an application level fallback. Disabling IPv6 is best done at an
+ * OS/network level, and/or configured properly in VPN setups. If you are not masking your IP,
+ * then this won't make much difference. If you are masking your IP, then it can only help.
+ * [NOTE] PHP defaults to IPv6 with "localhost". Use "php -S 127.0.0.1:PORT"
+ * [TEST] https://ipleak.org/
+ * [1] https://www.internetsociety.org/tag/ipv6-security/ (see Myths 2,4,5,6) ***/
+user_pref("network.dns.disableIPv6", true);
+/* 0702: disable HTTP2
+ * HTTP2 raises concerns with "multiplexing" and "server push", does nothing to
+ * enhance privacy, and opens up a number of server-side fingerprinting opportunities.
+ * [WARNING] Don't disable HTTP2. Don't be that one person using HTTP1.1 on HTTP2 sites
+ * [STATS] Over 50% of sites (April 2021) and growing [5]
+ * [1] https://http2.github.io/faq/
+ * [2] https://blog.scottlogic.com/2014/11/07/http-2-a-quick-look.html
+ * [3] https://http2.github.io/http2-spec/#rfc.section.10.8
+ * [4] https://queue.acm.org/detail.cfm?id=2716278
+ * [5] https://w3techs.com/technologies/details/ce-http2/all/all ***/
+   // user_pref("network.http.spdy.enabled", false);
+   // user_pref("network.http.spdy.enabled.deps", false);
+   // user_pref("network.http.spdy.enabled.http2", false);
+   // user_pref("network.http.spdy.websockets", false); // [FF65+]
+/* 0703: disable HTTP Alternative Services [FF37+]
+ * [SETUP-PERF] Relax this if you have FPI enabled (see 4000) *AND* you understand the
+ * consequences. FPI isolates these, but it was designed with the Tor protocol in mind,
+ * and the Tor Browser has extra protection, including enhanced sanitizing per Identity.
+ * [1] https://tools.ietf.org/html/rfc7838#section-9
+ * [2] https://www.mnot.net/blog/2016/03/09/alt-svc ***/
+user_pref("network.http.altsvc.enabled", false);
+user_pref("network.http.altsvc.oe", false);
+/* 0704: enforce the proxy server to do any DNS lookups when using SOCKS
+ * e.g. in Tor, this stops your local DNS server from knowing your Tor destination
+ * as a remote Tor node will handle the DNS request
+ * [1] https://trac.torproject.org/projects/tor/wiki/doc/TorifyHOWTO/WebBrowsers ***/
+user_pref("network.proxy.socks_remote_dns", true);
+/* 0708: disable FTP [FF60+] ***/
+   // user_pref("network.ftp.enabled", false); // [DEFAULT: false FF88+]
+/* 0709: disable using UNC (Uniform Naming Convention) paths [FF61+]
+ * [SETUP-CHROME] Can break extensions for profiles on network shares
+ * [1] https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/26424 ***/
+user_pref("network.file.disable_unc_paths", true); // [HIDDEN PREF]
+/* 0710: disable GIO as a potential proxy bypass vector
+ * Gvfs/GIO has a set of supported protocols like obex, network, archive, computer, dav, cdda,
+ * gphoto2, trash, etc. By default only smb and sftp protocols are accepted so far (as of FF64)
+ * [1] https://bugzilla.mozilla.org/1433507
+ * [2] https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/23044
+ * [3] https://en.wikipedia.org/wiki/GVfs
+ * [4] https://en.wikipedia.org/wiki/GIO_(software) ***/
+user_pref("network.gio.supported-protocols", ""); // [HIDDEN PREF]
+
+/*** [SECTION 0800]: LOCATION BAR / SEARCH BAR / SUGGESTIONS / HISTORY / FORMS
+     Change items 0850 and above to suit for privacy vs convenience and functionality. Consider
+     your environment (no unwanted eyeballs), your device (restricted access), your device's
+     unattended state (locked, encrypted, forensic hardened). Likewise, you may want to check
+     the items cleared on shutdown in section 2800.
+     [1] https://xkcd.com/538/
+***/
+user_pref("_user.js.parrot", "0800 syntax error: the parrot's ceased to be!");
+/* 0801: disable location bar using search
+ * Don't leak URL typos to a search engine, give an error message instead.
+ * Examples: "secretplace,com", "secretplace/com", "secretplace com", "secret place.com"
+ * [NOTE] This does **not** affect explicit user action such as using search buttons in the
+ * dropdown, or using keyword search shortcuts you configure in options (e.g. 'd' for DuckDuckGo)
+ * [SETUP-CHROME] If you don't, or rarely, type URLs, or you use a default search
+ * engine that respects privacy, then you probably don't need this ***/
+user_pref("keyword.enabled", false);
+/* 0802: disable location bar domain guessing
+ * domain guessing intercepts DNS "hostname not found errors" and resends a
+ * request (e.g. by adding www or .com). This is inconsistent use (e.g. FQDNs), does not work
+ * via Proxy Servers (different error), is a flawed use of DNS (TLDs: why treat .com
+ * as the 411 for DNS errors?), privacy issues (why connect to sites you didn't
+ * intend to), can leak sensitive data (e.g. query strings: e.g. Princeton attack),
+ * and is a security risk (e.g. common typos & malicious sites set up to exploit this) ***/
+user_pref("browser.fixup.alternate.enabled", false);
+/* 0803: display all parts of the url in the location bar ***/
+user_pref("browser.urlbar.trimURLs", false);
+/* 0805: disable coloring of visited links - CSS history leak
+ * [SETUP-HARDEN] Bulk rapid history sniffing was mitigated in 2010 [1][2]. Slower and more expensive
+ * redraw timing attacks were largely mitigated in FF77+ [3]. Using RFP (4501) further hampers timing
+ * attacks. Don't forget clearing history on close (2803). However, social engineering [2#limits][4][5]
+ * and advanced targeted timing attacks could still produce usable results
+ * [1] https://developer.mozilla.org/docs/Web/CSS/Privacy_and_the_:visited_selector
+ * [2] https://dbaron.org/mozilla/visited-privacy
+ * [3] https://bugzilla.mozilla.org/1632765
+ * [4] https://earthlng.github.io/testpages/visited_links.html (see github wiki APPENDIX A on how to use)
+ * [5] https://lcamtuf.blogspot.com/2016/08/css-mix-blend-mode-is-bad-for-keeping.html ***/
+   // user_pref("layout.css.visited_links_enabled", false);
+/* 0807: disable live search suggestions
+/* [NOTE] Both must be true for the location bar to work
+ * [SETUP-CHROME] Change these if you trust and use a privacy respecting search engine
+ * [SETTING] Search>Provide search suggestions | Show search suggestions in address bar results ***/
+user_pref("browser.search.suggest.enabled", false);
+user_pref("browser.urlbar.suggest.searches", false);
+/* 0810: disable location bar making speculative connections [FF56+]
+ * [1] https://bugzilla.mozilla.org/1348275 ***/
+user_pref("browser.urlbar.speculativeConnect.enabled", false);
+/* 0811: disable location bar leaking single words to a DNS provider **after searching** [FF78+]
+ * 0=never resolve single words, 1=heuristic (default), 2=always resolve
+ * [NOTE] For FF78 value 1 and 2 are the same and always resolve but that will change in future versions
+ * [1] https://bugzilla.mozilla.org/1642623 ***/
+user_pref("browser.urlbar.dnsResolveSingleWordsAfterSearch", 0);
+/* 0850a: disable location bar suggestion types
+ * [SETTING] Privacy & Security>Address Bar>When using the address bar, suggest ***/
+   // user_pref("browser.urlbar.suggest.history", false);
+   // user_pref("browser.urlbar.suggest.bookmark", false);
+   // user_pref("browser.urlbar.suggest.openpage", false);
+   // user_pref("browser.urlbar.suggest.topsites", false); // [FF78+]
+/* 0850b: disable tab-to-search [FF85+]
+ * Alternatively, you can exclude on a per-engine basis by unchecking them in Options>Search
+ * [SETTING] Privacy & Security>Address Bar>When using the address bar, suggest>Search engines ***/
+   // user_pref("browser.urlbar.suggest.engines", false);
+/* 0850c: disable location bar dropdown
+ * This value controls the total number of entries to appear in the location bar dropdown ***/
+   // user_pref("browser.urlbar.maxRichResults", 0);
+/* 0850d: disable location bar autofill
+ * [1] https://support.mozilla.org/en-US/kb/address-bar-autocomplete-firefox#w_url-autocomplete ***/
+   // user_pref("browser.urlbar.autoFill", false);
+/* 0860: disable search and form history
+ * [SETUP-WEB] Be aware that autocomplete form data can be read by third parties [1][2]
+ * [NOTE] We also clear formdata on exit (see 2803)
+ * [SETTING] Privacy & Security>History>Custom Settings>Remember search and form history
+ * [1] https://blog.mindedsecurity.com/2011/10/autocompleteagain.html
+ * [2] https://bugzilla.mozilla.org/381681 ***/
+user_pref("browser.formfill.enable", false);
+/* 0862: disable browsing and download history
+ * [NOTE] We also clear history and downloads on exiting Firefox (see 2803)
+ * [SETTING] Privacy & Security>History>Custom Settings>Remember browsing and download history ***/
+   // user_pref("places.history.enabled", false);
+/* 0870: disable Windows jumplist [WINDOWS] ***/
+user_pref("browser.taskbar.lists.enabled", false);
+user_pref("browser.taskbar.lists.frequent.enabled", false);
+user_pref("browser.taskbar.lists.recent.enabled", false);
+user_pref("browser.taskbar.lists.tasks.enabled", false);
+/* 0871: disable Windows taskbar preview [WINDOWS] ***/
+   // user_pref("browser.taskbar.previews.enable", false); // [DEFAULT: false]
+
+/*** [SECTION 0900]: PASSWORDS ***/
+user_pref("_user.js.parrot", "0900 syntax error: the parrot's expired!");
+/* 0901: disable saving passwords
+ * [NOTE] This does not clear any passwords already saved
+ * [SETTING] Privacy & Security>Logins and Passwords>Ask to save logins and passwords for websites ***/
+   // user_pref("signon.rememberSignons", false);
+/* 0902: use a primary password
+ * There are no preferences for this. It is all handled internally.
+ * [SETTING] Privacy & Security>Logins and Passwords>Use a Primary Password
+ * [1] https://support.mozilla.org/kb/use-primary-password-protect-stored-logins-and-pas ***/
+/* 0903: set how often Firefox should ask for the primary password
+ * 0=the first time (default), 1=every time it's needed, 2=every n minutes (see 0904) ***/
+user_pref("security.ask_for_password", 2);
+/* 0904: set how often in minutes Firefox should ask for the primary password (see 0903)
+ * in minutes, default is 30 ***/
+user_pref("security.password_lifetime", 5);
+/* 0905: disable auto-filling username & password form fields
+ * can leak in cross-site forms *and* be spoofed
+ * [NOTE] Username & password is still available when you enter the field
+ * [SETTING] Privacy & Security>Logins and Passwords>Autofill logins and passwords
+ * [1] https://freedom-to-tinker.com/2017/12/27/no-boundaries-for-user-identities-web-trackers-exploit-browser-login-managers/ ***/
+user_pref("signon.autofillForms", false);
+/* 0909: disable formless login capture for Password Manager [FF51+] ***/
+user_pref("signon.formlessCapture.enabled", false);
+/* 0912: limit (or disable) HTTP authentication credentials dialogs triggered by sub-resources [FF41+]
+ * hardens against potential credentials phishing
+ * 0=don't allow sub-resources to open HTTP authentication credentials dialogs
+ * 1=don't allow cross-origin sub-resources to open HTTP authentication credentials dialogs
+ * 2=allow sub-resources to open HTTP authentication credentials dialogs (default) ***/
+user_pref("network.auth.subresource-http-auth-allow", 1);
+
+/*** [SECTION 1000]: CACHE / SESSION (RE)STORE / FAVICONS
+     Cache tracking/fingerprinting techniques [1][2][3] require a cache. Disabling disk (1001)
+     *and* memory (1003) caches is one solution; but that's extreme and fingerprintable. A hardened
+     Temporary Containers configuration can effectively do the same thing, by isolating every tab [4].
+
+     We consider avoiding disk cache (1001) so cache is session/memory only (like Private Browsing
+     mode), and isolating cache to first party (4001) is sufficient and a good balance between
+     risk and performance. ETAGs can also be neutralized by modifying response headers [5], and
+     you can clear the cache manually or on a regular basis with an extension.
+
+     [1] https://en.wikipedia.org/wiki/HTTP_ETag#Tracking_using_ETags
+     [2] https://robertheaton.com/2014/01/20/cookieless-user-tracking-for-douchebags/
+     [3] https://www.grepular.com/Preventing_Web_Tracking_via_the_Browser_Cache
+     [4] https://medium.com/@stoically/enhance-your-privacy-in-firefox-with-temporary-containers-33925cd6cd21
+     [5] https://github.com/arkenfox/user.js/wiki/4.2.4-Header-Editor
+***/
+user_pref("_user.js.parrot", "1000 syntax error: the parrot's gone to meet 'is maker!");
+/** CACHE ***/
+/* 1001: disable disk cache
+ * [SETUP-PERF] If you think disk cache may help (heavy tab user, high-res video),
+ * or you use a hardened Temporary Containers, then feel free to override this
+ * [NOTE] We also clear cache on exiting Firefox (see 2803) ***/
+user_pref("browser.cache.disk.enable", false);
+/* 1003: disable memory cache
+ * capacity: -1=determine dynamically (default), 0=none, n=memory capacity in kibibytes ***/
+   // user_pref("browser.cache.memory.enable", false);
+   // user_pref("browser.cache.memory.capacity", 0);
+/* 1006: disable permissions manager from writing to disk [RESTART]
+ * [NOTE] This means any permission changes are session only
+ * [1] https://bugzilla.mozilla.org/967812 ***/
+   // user_pref("permissions.memory_only", true); // [HIDDEN PREF]
+/* 1007: disable media cache from writing to disk in Private Browsing
+ * [NOTE] MSE (Media Source Extensions) are already stored in-memory in PB
+ * [SETUP-WEB] ESR78: playback might break on subsequent loading (1650281) ***/
+user_pref("browser.privatebrowsing.forceMediaMemoryCache", true); // [FF75+]
+user_pref("media.memory_cache_max_size", 65536);
+
+/** SESSIONS & SESSION RESTORE ***/
+/* 1020: exclude "Undo Closed Tabs" in Session Restore ***/
+   // user_pref("browser.sessionstore.max_tabs_undo", 0);
+/* 1021: disable storing extra session data [SETUP-CHROME]
+ * extra session data contains contents of forms, scrollbar positions, cookies and POST data
+ * define on which sites to save extra session data:
+ * 0=everywhere, 1=unencrypted sites, 2=nowhere ***/
+user_pref("browser.sessionstore.privacy_level", 2);
+/* 1022: disable resuming session from crash ***/
+   // user_pref("browser.sessionstore.resume_from_crash", false);
+/* 1023: set the minimum interval between session save operations
+ * Increasing this can help on older machines and some websites, as well as reducing writes [1]
+ * Default is 15000 (15 secs). Try 30000 (30 secs), 60000 (1 min) etc
+ * [SETUP-CHROME] This can also affect entries in the "Recently Closed Tabs" feature:
+ * i.e. the longer the interval the more chance a quick tab open/close won't be captured.
+ * This longer interval *may* affect history but we cannot replicate any history not recorded
+ * [1] https://bugzilla.mozilla.org/1304389 ***/
+user_pref("browser.sessionstore.interval", 30000);
+/* 1024: disable automatic Firefox start and session restore after reboot [FF62+] [WINDOWS]
+ * [1] https://bugzilla.mozilla.org/603903 ***/
+user_pref("toolkit.winRegisterApplicationRestart", false);
+
+/** FAVICONS ***/
+/* 1030: disable favicons in shortcuts
+ * URL shortcuts use a cached randomly named .ico file which is stored in your
+ * profile/shortcutCache directory. The .ico remains after the shortcut is deleted.
+ * If set to false then the shortcuts use a generic Firefox icon ***/
+user_pref("browser.shell.shortcutFavicons", false);
+/* 1031: disable favicons in history and bookmarks
+ * Stored as data blobs in favicons.sqlite, these don't reveal anything that your
+ * actual history (and bookmarks) already do. Your history is more detailed, so
+ * control that instead; e.g. disable history, clear history on close, use PB mode
+ * [NOTE] favicons.sqlite is sanitized on Firefox close, not in-session ***/
+   // user_pref("browser.chrome.site_icons", false);
+/* 1032: disable favicons in web notifications ***/
+   // user_pref("alerts.showFavicons", false); // [DEFAULT: false]
+
+/*** [SECTION 1200]: HTTPS (SSL/TLS / OCSP / CERTS / HPKP / CIPHERS)
+   Your cipher and other settings can be used in server side fingerprinting
+   [TEST] https://www.ssllabs.com/ssltest/viewMyClient.html
+   [TEST] https://browserleaks.com/ssl
+   [TEST] https://ja3er.com/
+   [1] https://www.securityartwork.es/2017/02/02/tls-client-fingerprinting-with-bro/
+***/
+user_pref("_user.js.parrot", "1200 syntax error: the parrot's a stiff!");
+/** SSL (Secure Sockets Layer) / TLS (Transport Layer Security) ***/
+/* 1201: require safe negotiation
+ * Blocks connections (SSL_ERROR_UNSAFE_NEGOTIATION) to servers that don't support RFC 5746 [2]
+ * as they're potentially vulnerable to a MiTM attack [3]. A server without RFC 5746 can be
+ * safe from the attack if it disables renegotiations but the problem is that the browser can't
+ * know that. Setting this pref to true is the only way for the browser to ensure there will be
+ * no unsafe renegotiations on the channel between the browser and the server.
+ * [STATS] SSL Labs (Dec 2020) reports 99.0% of sites have secure renegotiation [4]
+ * [1] https://wiki.mozilla.org/Security:Renegotiation
+ * [2] https://tools.ietf.org/html/rfc5746
+ * [3] https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2009-3555
+ * [4] https://www.ssllabs.com/ssl-pulse/ ***/
+user_pref("security.ssl.require_safe_negotiation", true);
+/* 1202: control TLS versions with min and max
+ * 1=TLS 1.0, 2=TLS 1.1, 3=TLS 1.2, 4=TLS 1.3
+ * [WARNING] Leave these at default, otherwise you alter your TLS fingerprint.
+ * [1] https://www.ssllabs.com/ssl-pulse/ ***/
+   // user_pref("security.tls.version.min", 3); // [DEFAULT: 3]
+   // user_pref("security.tls.version.max", 4);
+/* 1203: enforce TLS 1.0 and 1.1 downgrades as session only ***/
+user_pref("security.tls.version.enable-deprecated", false);
+/* 1204: disable SSL session tracking [FF36+]
+ * SSL Session IDs are unique and last up to 24hrs in Firefox (or longer with prolongation attacks)
+ * [NOTE] These are not used in PB mode. In normal windows they are isolated when using FPI (4001)
+ * and/or containers. In FF85+ they are isolated by default (privacy.partition.network_state)
+ * [WARNING] There are perf and passive fingerprinting costs, for little to no gain. Preventing
+ * tracking via this method does not address IPs, nor handle any sanitizing of current identifiers
+ * [1] https://tools.ietf.org/html/rfc5077
+ * [2] https://bugzilla.mozilla.org/967977
+ * [3] https://arxiv.org/abs/1810.07304 ***/
+   // user_pref("security.ssl.disable_session_identifiers", true); // [HIDDEN PREF]
+/* 1206: disable TLS1.3 0-RTT (round-trip time) [FF51+]
+ * [1] https://github.com/tlswg/tls13-spec/issues/1001
+ * [2] https://blog.cloudflare.com/tls-1-3-overview-and-q-and-a/ ***/
+user_pref("security.tls.enable_0rtt_data", false);
+
+/** OCSP (Online Certificate Status Protocol)
+    [1] https://scotthelme.co.uk/revocation-is-broken/
+    [2] https://blog.mozilla.org/security/2013/07/29/ocsp-stapling-in-firefox/
+***/
+/* 1211: control when to use OCSP fetching (to confirm current validity of certificates)
+ * 0=disabled, 1=enabled (default), 2=enabled for EV certificates only
+ * OCSP (non-stapled) leaks information about the sites you visit to the CA (cert authority)
+ * It's a trade-off between security (checking) and privacy (leaking info to the CA)
+ * [NOTE] This pref only controls OCSP fetching and does not affect OCSP stapling
+ * [1] https://en.wikipedia.org/wiki/Ocsp ***/
+user_pref("security.OCSP.enabled", 1);
+/* 1212: set OCSP fetch failures (non-stapled, see 1211) to hard-fail [SETUP-WEB]
+ * When a CA cannot be reached to validate a cert, Firefox just continues the connection (=soft-fail)
+ * Setting this pref to true tells Firefox to instead terminate the connection (=hard-fail)
+ * It is pointless to soft-fail when an OCSP fetch fails: you cannot confirm a cert is still valid (it
+ * could have been revoked) and/or you could be under attack (e.g. malicious blocking of OCSP servers)
+ * [1] https://blog.mozilla.org/security/2013/07/29/ocsp-stapling-in-firefox/
+ * [2] https://www.imperialviolet.org/2014/04/19/revchecking.html ***/
+user_pref("security.OCSP.require", true);
+
+/** CERTS / HPKP (HTTP Public Key Pinning) ***/
+/* 1220: disable or limit SHA-1 certificates
+ * 0=all SHA1 certs are allowed
+ * 1=all SHA1 certs are blocked
+ * 2=deprecated option that now maps to 1
+ * 3=only allowed for locally-added roots (e.g. anti-virus)
+ * 4=only allowed for locally-added roots or for certs in 2015 and earlier
+ * [SETUP-CHROME] When disabled, some man-in-the-middle devices (e.g. security scanners and
+ * antivirus products, may fail to connect to HTTPS sites. SHA-1 is *almost* obsolete.
+ * [1] https://blog.mozilla.org/security/2016/10/18/phasing-out-sha-1-on-the-public-web/ ***/
+user_pref("security.pki.sha1_enforcement_level", 1);
+/* 1221: disable Windows 8.1's Microsoft Family Safety cert [FF50+] [WINDOWS]
+ * 0=disable detecting Family Safety mode and importing the root
+ * 1=only attempt to detect Family Safety mode (don't import the root)
+ * 2=detect Family Safety mode and import the root
+ * [1] https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/21686 ***/
+user_pref("security.family_safety.mode", 0);
+/* 1222: disable intermediate certificate caching (fingerprinting attack vector) [FF41+] [RESTART]
+ * [NOTE] This affects login/cert/key dbs. The effect is all credentials are session-only.
+ * Saved logins and passwords are not available. Reset the pref and restart to return them.
+ * [1] https://shiftordie.de/blog/2017/02/21/fingerprinting-firefox-users-with-cached-intermediate-ca-certificates-fiprinca/ ***/
+   // user_pref("security.nocertdb", true); // [HIDDEN PREF]
+/* 1223: enforce strict pinning
+ * PKP (Public Key Pinning) 0=disabled 1=allow user MiTM (such as your antivirus), 2=strict
+ * [SETUP-WEB] If you rely on an AV (antivirus) to protect your web browsing
+ * by inspecting ALL your web traffic, then leave at current default=1
+ * [1] https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/16206 ***/
+user_pref("security.cert_pinning.enforcement_level", 2);
+/* 1224: enforce CRLite [FF73+]
+ * In FF84+ it covers valid certs and in mode 2 doesn't fall back to OCSP
+ * [1] https://bugzilla.mozilla.org/buglist.cgi?bug_id=1429800,1670985
+ * [2] https://blog.mozilla.org/security/tag/crlite/ ***/
+user_pref("security.remote_settings.crlite_filters.enabled", true);
+user_pref("security.pki.crlite_mode", 2);
+
+/** MIXED CONTENT ***/
+/* 1240: enforce no insecure active content on https pages
+ * [1] https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/21323 ***/
+user_pref("security.mixed_content.block_active_content", true); // [DEFAULT: true]
+/* 1241: disable insecure passive content (such as images) on https pages [SETUP-WEB] ***/
+user_pref("security.mixed_content.block_display_content", true);
+/* 1244: enable HTTPS-Only mode [FF76+]
+ * When "https_only_mode" (all windows) is true, "https_only_mode_pbm" (private windows only) is ignored
+ * [SETTING] to add site exceptions: Padlock>HTTPS-Only mode>On/Off/Off temporarily
+ * [SETTING] Privacy & Security>HTTPS-Only Mode
+ * [TEST] http://example.com [upgrade]
+ * [TEST] http://neverssl.org/ [no upgrade]
+ * [1] https://bugzilla.mozilla.org/1613063 [META] ***/
+user_pref("dom.security.https_only_mode", true); // [FF76+]
+   // user_pref("dom.security.https_only_mode_pbm", true); // [FF80+]
+/* 1245: enable HTTPS-Only mode for local resources [FF77+] ***/
+   // user_pref("dom.security.https_only_mode.upgrade_local", true);
+/* 1246: disable HTTP background requests [FF82+]
+ * When attempting to upgrade, if the server doesn't respond within 3 seconds, firefox
+ * sends HTTP requests in order to check if the server supports HTTPS or not.
+ * This is done to avoid waiting for a timeout which takes 90 seconds
+ * [1] https://bugzilla.mozilla.org/buglist.cgi?bug_id=1642387,1660945 ***/
+user_pref("dom.security.https_only_mode_send_http_background_request", false);
+/* 1247: treat .onion as a secure context [FF60+] [TOR]
+ * [NOTE] Firefox cannot access .onion sites by default: it is strongly recommended you just use Tor Browser
+ * [1] https://bugzilla.mozilla.org/1382359 ***/
+   // user_pref("dom.securecontext.whitelist_onions", true);
+
+/** CIPHERS [WARNING: do not meddle with your cipher suite: see the section 1200 intro]
+ * These are all the ciphers still using SHA-1 and CBC which are weaker than the available alternatives. (see "Cipher Suites" in [1])
+ * Additionally some have other weaknesses like key sizes of 128 (or lower) [2] and/or no Perfect Forward Secrecy [3].
+ * [1] https://browserleaks.com/ssl
+ * [2] https://en.wikipedia.org/wiki/Key_size
+ * [3] https://en.wikipedia.org/wiki/Forward_secrecy
+ ***/
+/* 1261: disable 3DES (effective key size < 128 and no PFS)
+ * [1] https://en.wikipedia.org/wiki/3des#Security
+ * [2] https://en.wikipedia.org/wiki/Meet-in-the-middle_attack
+ * [3] https://www-archive.mozilla.org/projects/security/pki/nss/ssl/fips-ssl-ciphersuites.html ***/
+   // user_pref("security.ssl3.rsa_des_ede3_sha", false);
+/* 1264: disable the remaining non-modern cipher suites as of FF78 (in order of preferred by FF) ***/
+   // user_pref("security.ssl3.ecdhe_ecdsa_aes_256_sha", false);
+   // user_pref("security.ssl3.ecdhe_ecdsa_aes_128_sha", false);
+   // user_pref("security.ssl3.ecdhe_rsa_aes_128_sha", false);
+   // user_pref("security.ssl3.ecdhe_rsa_aes_256_sha", false);
+   // user_pref("security.ssl3.rsa_aes_128_sha", false); // no PFS
+   // user_pref("security.ssl3.rsa_aes_256_sha", false); // no PFS
+
+/** UI (User Interface) ***/
+/* 1270: display warning on the padlock for "broken security" (if 1201 is false)
+ * Bug: warning padlock not indicated for subresources on a secure page! [2]
+ * [1] https://wiki.mozilla.org/Security:Renegotiation
+ * [2] https://bugzilla.mozilla.org/1353705 ***/
+user_pref("security.ssl.treat_unsafe_negotiation_as_broken", true);
+/* 1271: control "Add Security Exception" dialog on SSL warnings
+ * 0=do neither 1=pre-populate url 2=pre-populate url + pre-fetch cert (default)
+ * [1] https://github.com/pyllyukko/user.js/issues/210 ***/
+user_pref("browser.ssl_override_behavior", 1);
+/* 1272: display advanced information on Insecure Connection warning pages
+ * only works when it's possible to add an exception
+ * i.e. it doesn't work for HSTS discrepancies (https://subdomain.preloaded-hsts.badssl.com/)
+ * [TEST] https://expired.badssl.com/ ***/
+user_pref("browser.xul.error_pages.expert_bad_cert", true);
+/* 1273: display "insecure" icon and "Not Secure" text on HTTP sites ***/
+   // user_pref("security.insecure_connection_icon.enabled", true); // [FF59+] [DEFAULT: true]
+user_pref("security.insecure_connection_text.enabled", true); // [FF60+]
+
+/*** [SECTION 1400]: FONTS ***/
+user_pref("_user.js.parrot", "1400 syntax error: the parrot's bereft of life!");
+/* 1401: disable websites choosing fonts (0=block, 1=allow)
+ * This can limit most (but not all) JS font enumeration which is a high entropy fingerprinting vector
+ * [WARNING] **DO NOT USE**: in FF80+ RFP covers this, and non-RFP users should use font vis (4618)
+ * [SETTING] General>Language and Appearance>Fonts & Colors>Advanced>Allow pages to choose... ***/
+   // user_pref("browser.display.use_document_fonts", 0);
+/* 1403: disable icon fonts (glyphs) and local fallback rendering
+ * [1] https://bugzilla.mozilla.org/789788
+ * [2] https://gitlab.torproject.org/legacy/trac/-/issues/8455 ***/
+   // user_pref("gfx.downloadable_fonts.enabled", false); // [FF41+]
+   // user_pref("gfx.downloadable_fonts.fallback_delay", -1);
+/* 1404: disable rendering of SVG OpenType fonts
+ * [1] https://wiki.mozilla.org/SVGOpenTypeFonts - iSECPartnersReport recommends to disable this ***/
+user_pref("gfx.font_rendering.opentype_svg.enabled", false);
+/* 1408: disable graphite
+ * Graphite has had many critical security issues in the past [1]
+ * [1] https://www.mozilla.org/security/advisories/mfsa2017-15/#CVE-2017-7778
+ * [2] https://en.wikipedia.org/wiki/Graphite_(SIL) ***/
+user_pref("gfx.font_rendering.graphite.enabled", false);
+/* 1409: limit system font exposure to a whitelist [FF52+] [RESTART]
+ * If the whitelist is empty, then whitelisting is considered disabled and all fonts are allowed
+ * [NOTE] In FF81+ the whitelist **overrides** RFP's font visibility (see 4618)
+ * [WARNING] **DO NOT USE**: in FF80+ RFP covers this, and non-RFP users should use font vis (4618)
+ * [1] https://bugzilla.mozilla.org/1121643 ***/
+   // user_pref("font.system.whitelist", ""); // [HIDDEN PREF]
+
+/*** [SECTION 1600]: HEADERS / REFERERS
+     Only *cross domain* referers need controlling: leave 1601, 1602, 1605 and 1606 alone
+     ---
+     Expect some breakage: Use an extension if you need precise control
+     ---
+                    full URI: https://example.com:8888/foo/bar.html?id=1234
+       scheme+host+port+path: https://example.com:8888/foo/bar.html
+            scheme+host+port: https://example.com:8888
+     ---
+     [1] https://feeding.cloud.geek.nz/posts/tweaking-referrer-for-privacy-in-firefox/
+***/
+user_pref("_user.js.parrot", "1600 syntax error: the parrot rests in peace!");
+/* 1601: ALL: control when images/links send a referer
+ * 0=never, 1=send only when links are clicked, 2=for links and images (default) ***/
+   // user_pref("network.http.sendRefererHeader", 2);
+/* 1602: ALL: control the amount of information to send
+ * 0=send full URI (default), 1=scheme+host+port+path, 2=scheme+host+port ***/
+   // user_pref("network.http.referer.trimmingPolicy", 0);
+/* 1603: CROSS ORIGIN: control when to send a referer
+ * 0=always (default), 1=only if base domains match, 2=only if hosts match
+ * [SETUP-WEB] Known to cause issues with older modems/routers and some sites e.g vimeo, icloud ***/
+user_pref("network.http.referer.XOriginPolicy", 2);
+/* 1604: CROSS ORIGIN: control the amount of information to send [FF52+]
+ * 0=send full URI (default), 1=scheme+host+port+path, 2=scheme+host+port ***/
+user_pref("network.http.referer.XOriginTrimmingPolicy", 2);
+/* 1605: ALL: disable spoofing a referer
+ * [WARNING] Do not set this to true, as spoofing effectively disables the anti-CSRF
+ * (Cross-Site Request Forgery) protections that some sites may rely on ***/
+   // user_pref("network.http.referer.spoofSource", false); // [DEFAULT: false]
+/* 1606: ALL: set the default Referrer Policy [FF59+]
+ * 0=no-referer, 1=same-origin, 2=strict-origin-when-cross-origin, 3=no-referrer-when-downgrade
+ * [NOTE] This is only a default, it can be overridden by a site-controlled Referrer Policy
+ * [1] https://www.w3.org/TR/referrer-policy/
+ * [2] https://developer.mozilla.org/docs/Web/HTTP/Headers/Referrer-Policy
+ * [3] https://blog.mozilla.org/security/2018/01/31/preventing-data-leaks-by-stripping-path-information-in-http-referrers/
+ * [4] https://blog.mozilla.org/security/2021/03/22/firefox-87-trims-http-referrers-by-default-to-protect-user-privacy/ ***/
+   // user_pref("network.http.referer.defaultPolicy", 2); // [DEFAULT: 2 FF87+]
+   // user_pref("network.http.referer.defaultPolicy.pbmode", 2); // [DEFAULT: 2]
+/* 1607: hide (not spoof) referrer when leaving a .onion domain [FF54+] [TOR]
+ * [NOTE] Firefox cannot access .onion sites by default: it is strongly recommended you just use Tor Browser
+ * [1] https://bugzilla.mozilla.org/1305144 ***/
+   // user_pref("network.http.referer.hideOnionSource", true);
+/* 1610: ALL: enable the DNT (Do Not Track) HTTP header
+ * [NOTE] DNT is enforced with Enhanced Tracking Protection regardless of this pref
+ * [SETTING] Privacy & Security>Enhanced Tracking Protection>Send websites a "Do Not Track" signal... ***/
+user_pref("privacy.donottrackheader.enabled", true);
+
+/*** [SECTION 1700]: CONTAINERS
+     If you want to *really* leverage containers, we highly recommend Temporary Containers [2].
+     Read the article by the extension author [3], and check out the github wiki/repo [4].
+     [1] https://wiki.mozilla.org/Security/Contextual_Identity_Project/Containers
+     [2] https://addons.mozilla.org/firefox/addon/temporary-containers/
+     [3] https://medium.com/@stoically/enhance-your-privacy-in-firefox-with-temporary-containers-33925cd6cd21
+     [4] https://github.com/stoically/temporary-containers/wiki
+***/
+user_pref("_user.js.parrot", "1700 syntax error: the parrot's bit the dust!");
+/* 1701: enable Container Tabs setting in preferences (see 1702) [FF50+]
+ * [1] https://bugzilla.mozilla.org/1279029 ***/
+user_pref("privacy.userContext.ui.enabled", true);
+/* 1702: enable Container Tabs [FF50+]
+ * [SETTING] General>Tabs>Enable Container Tabs ***/
+user_pref("privacy.userContext.enabled", true);
+/* 1703: set behaviour on "+ Tab" button to display container menu on left click [FF74+]
+ * [NOTE] The menu is always shown on long press and right click
+ * [SETTING] General>Tabs>Enable Container Tabs>Settings>Select a container for each new tab ***/
+   // user_pref("privacy.userContext.newTabContainerOnLeftClick.enabled", true);
+
+/*** [SECTION 1800]: PLUGINS ***/
+user_pref("_user.js.parrot", "1800 syntax error: the parrot's pushing up daisies!");
+/* 1820: disable GMP (Gecko Media Plugins)
+ * [1] https://wiki.mozilla.org/GeckoMediaPlugins ***/
+   // user_pref("media.gmp-provider.enabled", false);
+/* 1825: disable widevine CDM (Content Decryption Module)
+ * [NOTE] This is covered by the EME master switch (1830) ***/
+   // user_pref("media.gmp-widevinecdm.enabled", false);
+/* 1830: disable all DRM content (EME: Encryption Media Extension)
+ * [SETUP-WEB] e.g. Netflix, Amazon Prime, Hulu, HBO, Disney+, Showtime, Starz, DirectTV
+ * [SETTING] General>DRM Content>Play DRM-controlled content
+ * [TEST] https://bitmovin.com/demos/drm
+ * [1] https://www.eff.org/deeplinks/2017/10/drms-dead-canary-how-we-just-lost-web-what-we-learned-it-and-what-we-need-do-next ***/
+user_pref("media.eme.enabled", false);
+
+/*** [SECTION 2000]: MEDIA / CAMERA / MIC ***/
+user_pref("_user.js.parrot", "2000 syntax error: the parrot's snuffed it!");
+/* 2001: disable WebRTC (Web Real-Time Communication)
+ * [SETUP-WEB] WebRTC can leak your IP address from behind your VPN, but if this is not
+ * in your threat model, and you want Real-Time Communication, this is the pref for you
+ * [1] https://www.privacytools.io/#webrtc ***/
+user_pref("media.peerconnection.enabled", false);
+/* 2002: limit WebRTC IP leaks if using WebRTC
+ * In FF70+ these settings match Mode 4 (Mode 3 in older versions) [3]
+ * [TEST] https://browserleaks.com/webrtc
+ * [1] https://bugzilla.mozilla.org/buglist.cgi?bug_id=1189041,1297416,1452713
+ * [2] https://wiki.mozilla.org/Media/WebRTC/Privacy
+ * [3] https://tools.ietf.org/html/draft-ietf-rtcweb-ip-handling-12#section-5.2 ***/
+user_pref("media.peerconnection.ice.default_address_only", true);
+user_pref("media.peerconnection.ice.no_host", true); // [FF51+]
+user_pref("media.peerconnection.ice.proxy_only_if_behind_proxy", true); // [FF70+]
+/* 2010: disable WebGL (Web Graphics Library)
+ * [SETUP-WEB] When disabled, may break some websites. When enabled, provides high entropy,
+ * especially with readPixels(). Some of the other entropy is lessened with RFP (see 4501)
+ * [1] https://www.contextis.com/resources/blog/webgl-new-dimension-browser-exploitation/
+ * [2] https://security.stackexchange.com/questions/13799/is-webgl-a-security-concern ***/
+user_pref("webgl.disabled", true);
+user_pref("webgl.enable-webgl2", false);
+/* 2012: limit WebGL ***/
+user_pref("webgl.disable-fail-if-major-performance-caveat", true); // [DEFAULT: true FF86+]
+/* 2022: disable screensharing ***/
+user_pref("media.getusermedia.screensharing.enabled", false);
+user_pref("media.getusermedia.browser.enabled", false);
+user_pref("media.getusermedia.audiocapture.enabled", false);
+/* 2024: set a default permission for Camera/Microphone [FF58+]
+ * 0=always ask (default), 1=allow, 2=block
+ * [SETTING] to add site exceptions: Ctrl+I>Permissions>Use the Camera/Microphone
+ * [SETTING] to manage site exceptions: Options>Privacy & Security>Permissions>Camera/Microphone>Settings ***/
+   // user_pref("permissions.default.camera", 2);
+   // user_pref("permissions.default.microphone", 2);
+/* 2030: disable autoplay of HTML5 media [FF63+]
+ * 0=Allow all, 1=Block non-muted media (default in FF67+), 2=Prompt (removed in FF66), 5=Block all (FF69+)
+ * [NOTE] You can set exceptions under site permissions
+ * [SETTING] Privacy & Security>Permissions>Autoplay>Settings>Default for all websites ***/
+   // user_pref("media.autoplay.default", 5);
+/* 2031: disable autoplay of HTML5 media if you interacted with the site [FF78+]
+ * 0=sticky (default), 1=transient, 2=user
+ * Firefox's Autoplay Policy Documentation [PDF] is linked below via SUMO
+ * [NOTE] If you have trouble with some video sites, then add an exception (see 2030)
+ * [1] https://support.mozilla.org/questions/1293231 ***/
+user_pref("media.autoplay.blocking_policy", 2);
+
+/*** [SECTION 2200]: WINDOW MEDDLING & LEAKS / POPUPS ***/
+user_pref("_user.js.parrot", "2200 syntax error: the parrot's 'istory!");
+/* 2202: prevent scripts from moving and resizing open windows ***/
+user_pref("dom.disable_window_move_resize", true);
+/* 2203: open links targeting new windows in a new tab instead
+ * This stops malicious window sizes and some screen resolution leaks.
+ * You can still right-click a link and open in a new window.
+ * [TEST] https://arkenfox.github.io/TZP/tzp.html#screen
+ * [1] https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/9881 ***/
+user_pref("browser.link.open_newwindow", 3); // 1=most recent window or tab 2=new window, 3=new tab
+user_pref("browser.link.open_newwindow.restriction", 0);
+/* 2204: disable Fullscreen API (requires user interaction) to prevent screen-resolution leaks
+ * [NOTE] You can still manually toggle the browser's fullscreen state (F11),
+ * but this pref will disable embedded video/game fullscreen controls, e.g. youtube
+ * [TEST] https://arkenfox.github.io/TZP/tzp.html#screen ***/
+   // user_pref("full-screen-api.enabled", false);
+/* 2210: block popup windows
+ * [SETTING] Privacy & Security>Permissions>Block pop-up windows ***/
+user_pref("dom.disable_open_during_load", true);
+/* 2212: limit events that can cause a popup [SETUP-WEB]
+ * default FF86+: "change click dblclick auxclick mousedown mouseup pointerdown pointerup notificationclick reset submit touchend contextmenu ***/
+user_pref("dom.popup_allowed_events", "click dblclick mousedown pointerdown");
+
+/*** [SECTION 2300]: WEB WORKERS
+     A worker is a JS "background task" running in a global context, i.e. it is different from
+     the current window. Workers can spawn new workers (must be the same origin & scheme),
+     including service and shared workers. Shared workers can be utilized by multiple scripts and
+     communicate between browsing contexts (windows/tabs/iframes) and can even control your cache.
+
+     [1]    Web Workers: https://developer.mozilla.org/docs/Web/API/Web_Workers_API
+     [2]         Worker: https://developer.mozilla.org/docs/Web/API/Worker
+     [3] Service Worker: https://developer.mozilla.org/docs/Web/API/Service_Worker_API
+     [4]   SharedWorker: https://developer.mozilla.org/docs/Web/API/SharedWorker
+     [5]   ChromeWorker: https://developer.mozilla.org/docs/Web/API/ChromeWorker
+     [6]  Notifications: https://support.mozilla.org/questions/1165867#answer-981820
+***/
+user_pref("_user.js.parrot", "2300 syntax error: the parrot's off the twig!");
+/* 2302: disable service workers [FF32, FF44-compat]
+ * Service workers essentially act as proxy servers that sit between web apps, and the
+ * browser and network, are event driven, and can control the web page/site it is associated
+ * with, intercepting and modifying navigation and resource requests, and caching resources.
+ * [NOTE] Service worker APIs are hidden (in Firefox) and cannot be used when in PB mode.
+ * [NOTE] Service workers only run over HTTPS. Service workers have no DOM access.
+ * [SETUP-WEB] Disabling service workers will break some sites. This pref is required true for
+ * service worker notifications (2304), push notifications (disabled, 2305) and service worker
+ * cache (2740). If you enable this pref, then check those settings as well ***/
+user_pref("dom.serviceWorkers.enabled", false);
+/* 2304: disable Web Notifications
+ * [NOTE] Web Notifications can also use service workers (2302) and are behind a prompt (2306)
+ * [1] https://developer.mozilla.org/docs/Web/API/Notifications_API ***/
+   // user_pref("dom.webnotifications.enabled", false); // [FF22+]
+   // user_pref("dom.webnotifications.serviceworker.enabled", false); // [FF44+]
+/* 2305: disable Push Notifications [FF44+]
+ * Push is an API that allows websites to send you (subscribed) messages even when the site
+ * isn't loaded, by pushing messages to your userAgentID through Mozilla's Push Server.
+ * [NOTE] Push requires service workers (2302) to subscribe to and display, and is behind
+ * a prompt (2306). Disabling service workers alone doesn't stop Firefox polling the
+ * Mozilla Push Server. To remove all subscriptions, reset your userAgentID (in about:config
+ * or on start), and you will get a new one within a few seconds.
+ * [1] https://support.mozilla.org/en-US/kb/push-notifications-firefox
+ * [2] https://developer.mozilla.org/en-US/docs/Web/API/Push_API ***/
+user_pref("dom.push.enabled", false);
+   // user_pref("dom.push.userAgentID", "");
+/* 2306: set a default permission for Notifications (both 2304 and 2305) [FF58+]
+ * 0=always ask (default), 1=allow, 2=block
+ * [NOTE] Best left at default "always ask", fingerprintable via Permissions API
+ * [SETTING] to add site exceptions: Ctrl+I>Permissions>Receive Notifications
+ * [SETTING] to manage site exceptions: Options>Privacy & Security>Permissions>Notifications>Settings ***/
+   // user_pref("permissions.default.desktop-notification", 2);
+
+/*** [SECTION 2400]: DOM (DOCUMENT OBJECT MODEL) & JAVASCRIPT ***/
+user_pref("_user.js.parrot", "2400 syntax error: the parrot's kicked the bucket!");
+/* 2401: disable website control over browser right-click context menu
+ * [NOTE] Shift-Right-Click will always bring up the browser right-click context menu ***/
+   // user_pref("dom.event.contextmenu.enabled", false);
+/* 2402: disable website access to clipboard events/content [SETUP-HARDEN]
+ * [NOTE] This will break some sites' functionality e.g. Outlook, Twitter, Facebook, Wordpress
+ * This applies to onCut/onCopy/onPaste events - i.e. it requires interaction with the website
+ * [WARNING] In FF88 or lower, with clipboardevents enabled, if both 'middlemouse.paste' and
+ * 'general.autoScroll' are true (at least one is default false) then the clipboard can leak [1]
+ * [1] https://bugzilla.mozilla.org/1528289 ***/
+   // user_pref("dom.event.clipboardevents.enabled", false);
+/* 2404: disable clipboard commands (cut/copy) from "non-privileged" content [FF41+]
+ * this disables document.execCommand("cut"/"copy") to protect your clipboard
+ * [1] https://bugzilla.mozilla.org/1170911 ***/
+user_pref("dom.allow_cut_copy", false);
+/* 2405: disable "Confirm you want to leave" dialog on page close
+ * Does not prevent JS leaks of the page close event.
+ * [1] https://developer.mozilla.org/docs/Web/Events/beforeunload
+ * [2] https://support.mozilla.org/questions/1043508 ***/
+user_pref("dom.disable_beforeunload", true);
+/* 2414: disable shaking the screen ***/
+user_pref("dom.vibrator.enabled", false);
+/* 2420: disable asm.js [FF22+] [SETUP-PERF]
+ * [1] http://asmjs.org/
+ * [2] https://www.mozilla.org/security/advisories/mfsa2015-29/
+ * [3] https://www.mozilla.org/security/advisories/mfsa2015-50/
+ * [4] https://www.mozilla.org/security/advisories/mfsa2017-01/#CVE-2017-5375
+ * [5] https://www.mozilla.org/security/advisories/mfsa2017-05/#CVE-2017-5400
+ * [6] https://rh0dev.github.io/blog/2017/the-return-of-the-jit/ ***/
+user_pref("javascript.options.asmjs", false);
+/* 2421: disable Ion and baseline JIT to harden against JS exploits [SETUP-HARDEN]
+ * [NOTE] In FF75+, when **both** Ion and JIT are disabled, **and** the new
+ * hidden pref is enabled, then Ion can still be used by extensions (1599226)
+ * [WARNING] Disabling Ion/JIT can cause some site issues and performance loss
+ * [1] https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-0817 ***/
+   // user_pref("javascript.options.ion", false);
+   // user_pref("javascript.options.baselinejit", false);
+   // user_pref("javascript.options.jit_trustedprincipals", true); // [FF75+] [HIDDEN PREF]
+/* 2422: disable WebAssembly [FF52+]
+ * Vulnerabilities have increasingly been found, including those known and fixed
+ * in native programs years ago [2]. WASM has powerful low-level access, making
+ * certain attacks (brute-force) and vulnerabilities more possible
+ * [STATS] ~0.2% of websites, about half of which are for crytopmining / malvertising [2][3]
+ * [1] https://developer.mozilla.org/docs/WebAssembly
+ * [2] https://spectrum.ieee.org/tech-talk/telecom/security/more-worries-over-the-security-of-web-assembly
+ * [3] https://www.zdnet.com/article/half-of-the-websites-using-webassembly-use-it-for-malicious-purposes ***/
+user_pref("javascript.options.wasm", false);
+/* 2429: enable (limited but sufficient) window.opener protection [FF65+]
+ * Makes rel=noopener implicit for target=_blank in anchor and area elements when no rel attribute is set ***/
+user_pref("dom.targetBlankNoOpener.enabled", true); // [DEFAULT: true FF79+]
+
+/*** [SECTION 2500]: HARDWARE FINGERPRINTING ***/
+user_pref("_user.js.parrot", "2500 syntax error: the parrot's shuffled off 'is mortal coil!");
+/* 2502: disable Battery Status API
+ * Initially a Linux issue (high precision readout) that was fixed.
+ * However, it is still another metric for fingerprinting, used to raise entropy.
+ * e.g. do you have a battery or not, current charging status, charge level, times remaining etc
+ * [NOTE] From FF52+ Battery Status API is only available in chrome/privileged code [1]
+ * [1] https://bugzilla.mozilla.org/1313580 ***/
+   // user_pref("dom.battery.enabled", false);
+/* 2505: disable media device enumeration [FF29+]
+ * [NOTE] media.peerconnection.enabled should also be set to false (see 2001)
+ * [1] https://wiki.mozilla.org/Media/getUserMedia
+ * [2] https://developer.mozilla.org/docs/Web/API/MediaDevices/enumerateDevices ***/
+user_pref("media.navigator.enabled", false);
+/* 2508: disable hardware acceleration to reduce graphics fingerprinting [SETUP-HARDEN]
+ * [WARNING] Affects text rendering (fonts will look different), impacts video performance,
+ * and parts of Quantum that utilize the GPU will also be affected as they are rolled out
+ * [SETTING] General>Performance>Custom>Use hardware acceleration when available
+ * [1] https://wiki.mozilla.org/Platform/GFX/HardwareAcceleration ***/
+   // user_pref("gfx.direct2d.disabled", true); // [WINDOWS]
+   // user_pref("layers.acceleration.disabled", true);
+/* 2510: disable Web Audio API [FF51+]
+ * [1] https://bugzilla.mozilla.org/1288359 ***/
+user_pref("dom.webaudio.enabled", false);
+/* 2517: disable Media Capabilities API [FF63+]
+ * [WARNING] This *may* affect media performance if disabled, no one is sure
+ * [1] https://github.com/WICG/media-capabilities
+ * [2] https://wicg.github.io/media-capabilities/#security-privacy-considerations ***/
+   // user_pref("media.media-capabilities.enabled", false);
+/* 2520: disable virtual reality devices
+ * Optional protection depending on your connected devices
+ * [1] https://developer.mozilla.org/docs/Web/API/WebVR_API ***/
+   // user_pref("dom.vr.enabled", false);
+/* 2521: set a default permission for Virtual Reality (see 2520) [FF73+]
+ * 0=always ask (default), 1=allow, 2=block
+ * [SETTING] to add site exceptions: Ctrl+I>Permissions>Access Virtual Reality Devices
+ * [SETTING] to manage site exceptions: Options>Privacy & Security>Permissions>Virtual Reality>Settings ***/
+   // user_pref("permissions.default.xr", 2);
+
+/*** [SECTION 2600]: MISCELLANEOUS ***/
+user_pref("_user.js.parrot", "2600 syntax error: the parrot's run down the curtain!");
+/* 2601: prevent accessibility services from accessing your browser [RESTART]
+ * [SETTING] Privacy & Security>Permissions>Prevent accessibility services from accessing your browser (FF80 or lower)
+ * [1] https://support.mozilla.org/kb/accessibility-services ***/
+user_pref("accessibility.force_disabled", 1);
+/* 2602: disable sending additional analytics to web servers
+ * [1] https://developer.mozilla.org/docs/Web/API/Navigator/sendBeacon ***/
+user_pref("beacon.enabled", false);
+/* 2603: remove temp files opened with an external application
+ * [1] https://bugzilla.mozilla.org/302433 ***/
+user_pref("browser.helperApps.deleteTempFileOnExit", true);
+/* 2604: disable page thumbnail collection ***/
+user_pref("browser.pagethumbnails.capturing_disabled", true); // [HIDDEN PREF]
+/* 2606: disable UITour backend so there is no chance that a remote page can use it ***/
+user_pref("browser.uitour.enabled", false);
+user_pref("browser.uitour.url", "");
+/* 2607: disable various developer tools in browser context
+ * [SETTING] Devtools>Advanced Settings>Enable browser chrome and add-on debugging toolboxes
+ * [1] https://github.com/pyllyukko/user.js/issues/179#issuecomment-246468676 ***/
+user_pref("devtools.chrome.enabled", false);
+/* 2608: reset remote debugging to disabled
+ * [1] https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/16222 ***/
+user_pref("devtools.debugger.remote-enabled", false); // [DEFAULT: false]
+/* 2609: disable MathML (Mathematical Markup Language) [FF51+] [SETUP-HARDEN]
+ * [TEST] https://arkenfox.github.io/TZP/tzp.html#misc
+ * [1] https://bugzilla.mozilla.org/1173199 ***/
+   // user_pref("mathml.disabled", true);
+/* 2610: disable in-content SVG (Scalable Vector Graphics) [FF53+]
+ * [WARNING] Expect breakage incl. youtube player controls. Best left for a "hardened" profile.
+ * [1] https://bugzilla.mozilla.org/1216893 ***/
+   // user_pref("svg.disabled", true);
+/* 2611: disable middle mouse click opening links from clipboard
+ * [1] https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/10089 ***/
+user_pref("middlemouse.contentLoadURL", false);
+/* 2615: disable websites overriding Firefox's keyboard shortcuts [FF58+]
+ * 0 (default) or 1=allow, 2=block
+ * [SETTING] to add site exceptions: Ctrl+I>Permissions>Override Keyboard Shortcuts ***/
+   // user_pref("permissions.default.shortcuts", 2);
+/* 2616: remove special permissions for certain mozilla domains [FF35+]
+ * [1] resource://app/defaults/permissions ***/
+user_pref("permissions.manager.defaultsUrl", "");
+/* 2617: remove webchannel whitelist ***/
+user_pref("webchannel.allowObject.urlWhitelist", "");
+/* 2619: enforce Punycode for Internationalized Domain Names to eliminate possible spoofing
+ * Firefox has *some* protections, but it is better to be safe than sorry
+ * [SETUP-WEB] Might be undesirable for non-latin alphabet users since legitimate IDN's are also punycoded
+ * [TEST] https://www.xn--80ak6aa92e.com/ (www.apple.com)
+ * [1] https://wiki.mozilla.org/IDN_Display_Algorithm
+ * [2] https://en.wikipedia.org/wiki/IDN_homograph_attack
+ * [3] CVE-2017-5383: https://www.mozilla.org/security/advisories/mfsa2017-02/
+ * [4] https://www.xudongz.com/blog/2017/idn-phishing/ ***/
+user_pref("network.IDN_show_punycode", true);
+/* 2620: enforce PDFJS, disable PDFJS scripting [SETUP-CHROME]
+ * This setting controls if the option "Display in Firefox" is available in the setting below
+ *   and by effect controls whether PDFs are handled in-browser or externally ("Ask" or "Open With")
+ * PROS: pdfjs is lightweight, open source, and as secure/vetted as any pdf reader out there (more than most)
+ *   Exploits are rare (one serious case in seven years), treated seriously and patched quickly.
+ *   It doesn't break "state separation" of browser content (by not sharing with OS, independent apps).
+ *   It maintains disk avoidance and application data isolation. It's convenient. You can still save to disk.
+ * CONS: You may prefer a different pdf reader for security reasons
+ * CAVEAT: JS can still force a pdf to open in-browser by bundling its own code (rare)
+ * [SETTING] General>Applications>Portable Document Format (PDF) ***/
+user_pref("pdfjs.disabled", false); // [DEFAULT: false]
+user_pref("pdfjs.enableScripting", false); // [FF86+]
+/* 2621: disable links launching Windows Store on Windows 8/8.1/10 [WINDOWS] ***/
+user_pref("network.protocol-handler.external.ms-windows-store", false);
+/* 2622: enforce no system colors; they can be fingerprinted
+ * [SETTING] General>Language and Appearance>Fonts and Colors>Colors>Use system colors ***/
+user_pref("browser.display.use_system_colors", false); // [DEFAULT: false]
+/* 2623: disable permissions delegation [FF73+]
+ * Currently applies to cross-origin geolocation, camera, mic and screen-sharing
+ * permissions, and fullscreen requests. Disabling delegation means any prompts
+ * for these will show/use their correct 3rd party origin
+ * [1] https://groups.google.com/forum/#!topic/mozilla.dev.platform/BdFOMAuCGW8/discussion ***/
+user_pref("permissions.delegation.enabled", false);
+/* 2624: enable "window.name" protection [FF82+]
+ * If a new page from another domain is loaded into a tab, then window.name is set to an empty string. The original
+ * string is restored if the tab reverts back to the original page. This change prevents some cross-site attacks
+ * [TEST] https://arkenfox.github.io/TZP/tests/windownamea.html ***/
+user_pref("privacy.window.name.update.enabled", true); // [DEFAULT: true FF86+]
+/* 2625: disable bypassing 3rd party extension install prompts [FF82+]
+ * [1] https://bugzilla.mozilla.org/buglist.cgi?bug_id=1659530,1681331 ***/
+user_pref("extensions.postDownloadThirdPartyPrompt", false);
+
+/** DOWNLOADS ***/
+/* 2650: discourage downloading to desktop
+ * 0=desktop, 1=downloads (default), 2=last used
+ * [SETTING] To set your default "downloads": General>Downloads>Save files to ***/
+   // user_pref("browser.download.folderList", 2);
+/* 2651: enforce user interaction for security by always asking where to download
+ * [SETUP-CHROME] On Android this blocks longtapping and saving images
+ * [SETTING] General>Downloads>Always ask you where to save files ***/
+user_pref("browser.download.useDownloadDir", false);
+/* 2652: disable adding downloads to the system's "recent documents" list ***/
+user_pref("browser.download.manager.addToRecentDocs", false);
+/* 2654: disable "open with" in download dialog [FF50+] [SETUP-HARDEN]
+ * This is very useful to enable when the browser is sandboxed (e.g. via AppArmor)
+ * in such a way that it is forbidden to run external applications.
+ * [WARNING] This may interfere with some users' workflow or methods
+ * [1] https://bugzilla.mozilla.org/1281959 ***/
+   // user_pref("browser.download.forbid_open_with", true);
+
+/** EXTENSIONS ***/
+/* 2660: lock down allowed extension directories
+ * [SETUP-CHROME] This will break extensions, language packs, themes and any other
+ * XPI files which are installed outside of profile and application directories
+ * [1] https://mike.kaply.com/2012/02/21/understanding-add-on-scopes/
+ * [1] archived: https://archive.is/DYjAM ***/
+user_pref("extensions.enabledScopes", 5); // [HIDDEN PREF]
+user_pref("extensions.autoDisableScopes", 15); // [DEFAULT: 15]
+/* 2662: disable webextension restrictions on certain mozilla domains (you also need 4503) [FF60+]
+ * [1] https://bugzilla.mozilla.org/buglist.cgi?bug_id=1384330,1406795,1415644,1453988 ***/
+   // user_pref("extensions.webextensions.restrictedDomains", "");
+
+/** SECURITY ***/
+/* 2680: enforce CSP (Content Security Policy)
+ * [WARNING] CSP is a very important and widespread security feature. Don't disable it!
+ * [1] https://developer.mozilla.org/docs/Web/HTTP/CSP ***/
+user_pref("security.csp.enable", true); // [DEFAULT: true]
+/* 2684: enforce a security delay on some confirmation dialogs such as install, open/save
+ * [1] https://www.squarefree.com/2004/07/01/race-conditions-in-security-dialogs/ ***/
+user_pref("security.dialog_enable_delay", 700);
+
+/*** [SECTION 2700]: PERSISTENT STORAGE
+     Data SET by websites including
+            cookies : profile\cookies.sqlite
+       localStorage : profile\webappsstore.sqlite
+          indexedDB : profile\storage\default
+           appCache : profile\OfflineCache
+     serviceWorkers :
+
+     [NOTE] indexedDB and serviceWorkers are not available in Private Browsing Mode
+     [NOTE] Blocking cookies also blocks websites access to: localStorage (incl. sessionStorage),
+     indexedDB, sharedWorker, and serviceWorker (and therefore service worker cache and notifications)
+     If you set a site exception for cookies (either "Allow" or "Allow for Session") then they become
+     accessible to websites except shared/service workers where the cookie setting *must* be "Allow"
+***/
+user_pref("_user.js.parrot", "2700 syntax error: the parrot's joined the bleedin' choir invisible!");
+/* 2701: disable or isolate 3rd-party cookies and site-data [SETUP-WEB]
+ * 0 = Accept cookies and site data
+ * 1 = (Block) All third-party cookies
+ * 2 = (Block) All cookies
+ * 3 = (Block) Cookies from unvisited websites
+ * 4 = (Block) Cross-site tracking cookies (default)
+ * 5 = (Isolate All) Cross-site cookies (TCP: Total Cookie Protection / dFPI: dynamic FPI) [1] (FF86+)
+ * Option 5 with FPI enabled (4001) is ignored and not shown, and option 4 used instead
+ * [NOTE] You can set cookie exceptions under site permissions or use an extension
+ * [NOTE] Enforcing category to custom ensures ETP related prefs are always honored
+ * [SETTING] Privacy & Security>Enhanced Tracking Protection>Custom>Cookies
+ * [1] https://blog.mozilla.org/security/2021/02/23/total-cookie-protection/ ***/
+user_pref("network.cookie.cookieBehavior", 1);
+user_pref("browser.contentblocking.category", "custom");
+/* 2702: set third-party cookies (if enabled, see 2701) to session-only
+ * [NOTE] .sessionOnly overrides .nonsecureSessionOnly except when .sessionOnly=false and
+ * .nonsecureSessionOnly=true. This allows you to keep HTTPS cookies, but session-only HTTP ones
+ * [1] https://feeding.cloud.geek.nz/posts/tweaking-cookies-for-privacy-in-firefox/ ***/
+user_pref("network.cookie.thirdparty.sessionOnly", true);
+user_pref("network.cookie.thirdparty.nonsecureSessionOnly", true); // [FF58+]
+/* 2703: delete cookies and site data on close
+ * 0=keep until they expire (default), 2=keep until you close Firefox
+ * [NOTE] The setting below is disabled (but not changed) if you block all cookies (2701 = 2)
+ * [SETTING] Privacy & Security>Cookies and Site Data>Delete cookies and site data when Firefox is closed ***/
+   // user_pref("network.cookie.lifetimePolicy", 2);
+/* 2710: enable Enhanced Tracking Protection (ETP) in all windows
+ * [SETTING] Privacy & Security>Enhanced Tracking Protection>Custom>Tracking content
+ * [SETTING] to add site exceptions: Urlbar>ETP Shield
+ * [SETTING] to manage site exceptions: Options>Privacy & Security>Enhanced Tracking Protection>Manage Exceptions ***/
+user_pref("privacy.trackingprotection.enabled", true);
+/* 2711: enable various ETP lists ***/
+user_pref("privacy.trackingprotection.socialtracking.enabled", true);
+   // user_pref("privacy.trackingprotection.cryptomining.enabled", true); // [DEFAULT: true]
+   // user_pref("privacy.trackingprotection.fingerprinting.enabled", true); // [DEFAULT: true]
+/* 2720: disable DOM (Document Object Model) Storage
+ * [WARNING] This will break a LOT of sites' functionality AND extensions!
+ * You are better off using an extension for more granular control ***/
+   // user_pref("dom.storage.enabled", false);
+/* 2730: enforce no offline cache storage (appCache)
+ * The API is easily fingerprinted, use the "storage" pref instead ***/
+   // user_pref("browser.cache.offline.enable", false);
+user_pref("browser.cache.offline.storage.enable", false); // [FF71+] [DEFAULT: false FF84+]
+/* 2740: disable service worker cache and cache storage
+ * [NOTE] We clear service worker cache on exiting Firefox (see 2803)
+ * [1] https://w3c.github.io/ServiceWorker/#privacy ***/
+   // user_pref("dom.caches.enabled", false);
+/* 2750: disable Storage API [FF51+]
+ * The API gives sites the ability to find out how much space they can use, how much
+ * they are already using, and even control whether or not they need to be alerted
+ * before the user agent disposes of site data in order to make room for other things.
+ * [1] https://developer.mozilla.org/docs/Web/API/StorageManager
+ * [2] https://developer.mozilla.org/docs/Web/API/Storage_API
+ * [3] https://blog.mozilla.org/l10n/2017/03/07/firefox-l10n-report-aurora-54/ ***/
+   // user_pref("dom.storageManager.enabled", false);
+/* 2755: disable Storage Access API [FF65+]
+ * [1] https://developer.mozilla.org/en-US/docs/Web/API/Storage_Access_API ***/
+   // user_pref("dom.storage_access.enabled", false);
+/* 2760: enable Local Storage Next Generation (LSNG) [FF65+] ***/
+user_pref("dom.storage.next_gen", true);
+
+/*** [SECTION 2800]: SHUTDOWN
+     You should set the values to what suits you best.
+     - "Offline Website Data" includes appCache (2730), localStorage (2720),
+       service worker cache (2740), and QuotaManager (IndexedDB, asm-cache)
+     - In both 2803 + 2804, the 'download' and 'history' prefs are combined in the
+       Firefox interface as "Browsing & Download History" and their values will be synced
+***/
+user_pref("_user.js.parrot", "2800 syntax error: the parrot's bleedin' demised!");
+/* 2802: enable Firefox to clear items on shutdown (see 2803)
+ * [SETTING] Privacy & Security>History>Custom Settings>Clear history when Firefox closes ***/
+user_pref("privacy.sanitize.sanitizeOnShutdown", true);
+/* 2803: set what items to clear on shutdown (if 2802 is true) [SETUP-CHROME]
+ * [NOTE] If 'history' is true, downloads will also be cleared regardless of the value
+ * but if 'history' is false, downloads can still be cleared independently
+ * However, this may not always be the case. The interface combines and syncs these
+ * prefs when set from there, and the sanitize code may change at any time
+ * [SETTING] Privacy & Security>History>Custom Settings>Clear history when Firefox closes>Settings ***/
+user_pref("privacy.clearOnShutdown.cache", true);
+user_pref("privacy.clearOnShutdown.cookies", true);
+user_pref("privacy.clearOnShutdown.downloads", true); // see note above
+user_pref("privacy.clearOnShutdown.formdata", true); // Form & Search History
+user_pref("privacy.clearOnShutdown.history", true); // Browsing & Download History
+user_pref("privacy.clearOnShutdown.offlineApps", true); // Offline Website Data
+user_pref("privacy.clearOnShutdown.sessions", true); // Active Logins
+user_pref("privacy.clearOnShutdown.siteSettings", false); // Site Preferences
+/* 2804: reset default items to clear with Ctrl-Shift-Del (to match 2803) [SETUP-CHROME]
+ * This dialog can also be accessed from the menu History>Clear Recent History
+ * Firefox remembers your last choices. This will reset them when you start Firefox.
+ * [NOTE] Regardless of what you set privacy.cpd.downloads to, as soon as the dialog
+ * for "Clear Recent History" is opened, it is synced to the same as 'history' ***/
+user_pref("privacy.cpd.cache", true);
+user_pref("privacy.cpd.cookies", true);
+   // user_pref("privacy.cpd.downloads", true); // not used, see note above
+user_pref("privacy.cpd.formdata", true); // Form & Search History
+user_pref("privacy.cpd.history", true); // Browsing & Download History
+user_pref("privacy.cpd.offlineApps", true); // Offline Website Data
+user_pref("privacy.cpd.passwords", false); // this is not listed
+user_pref("privacy.cpd.sessions", true); // Active Logins
+user_pref("privacy.cpd.siteSettings", false); // Site Preferences
+/* 2805: clear Session Restore data when sanitizing on shutdown or manually [FF34+]
+ * [NOTE] Not needed if Session Restore is not used (see 0102) or is already cleared with history (see 2803)
+ * [NOTE] privacy.clearOnShutdown.openWindows prevents resuming from crashes (see 1022)
+ * [NOTE] privacy.cpd.openWindows has a bug that causes an additional window to open ***/
+   // user_pref("privacy.clearOnShutdown.openWindows", true);
+   // user_pref("privacy.cpd.openWindows", true);
+/* 2806: reset default 'Time range to clear' for 'Clear Recent History' (see 2804)
+ * Firefox remembers your last choice. This will reset the value when you start Firefox.
+ * 0=everything, 1=last hour, 2=last two hours, 3=last four hours,
+ * 4=today, 5=last five minutes, 6=last twenty-four hours
+ * [NOTE] The values 5 + 6 are not listed in the dropdown, which will display a
+ * blank value if they are used, but they do work as advertised ***/
+user_pref("privacy.sanitize.timeSpan", 0);
+
+/*** [SECTION 4000]: FPI (FIRST PARTY ISOLATION)
+   1278037 - indexedDB (FF51+)
+   1277803 - favicons (FF52+)
+   1264562 - OCSP cache (FF52+)
+   1268726 - Shared Workers (FF52+)
+   1316283 - SSL session cache (FF52+)
+   1317927 - media cache (FF53+)
+   1323644 - HSTS and HPKP (FF54+)
+   1334690 - HTTP Alternative Services (FF54+)
+   1334693 - SPDY/HTTP2 (FF55+)
+   1337893 - DNS cache (FF55+)
+   1344170 - blob: URI (FF55+)
+   1300671 - data:, about: URLs (FF55+)
+   1473247 - IP addresses (FF63+)
+   1492607 - postMessage with targetOrigin "*" (requires 4002) (FF65+)
+   1542309 - top-level domain URLs when host is in the public suffix list (FF68+)
+   1506693 - pdfjs range-based requests (FF68+)
+   1330467 - site permissions (FF69+)
+   1534339 - IPv6 (FF73+)
+***/
+user_pref("_user.js.parrot", "4000 syntax error: the parrot's pegged out");
+/* 4001: enable First Party Isolation [FF51+]
+ * [SETUP-WEB] May break cross-domain logins and site functionality until perfected
+ * [1] https://bugzilla.mozilla.org/buglist.cgi?bug_id=1260931,1299996 ***/
+user_pref("privacy.firstparty.isolate", true);
+/* 4002: enforce FPI restriction for window.opener [FF54+]
+ * [NOTE] Setting this to false may reduce the breakage in 4001
+ * FF65+ blocks postMessage with targetOrigin "*" if originAttributes don't match. But
+ * to reduce breakage it ignores the 1st-party domain (FPD) originAttribute [2][3]
+ * The 2nd pref removes that limitation and will only allow communication if FPDs also match.
+ * [1] https://bugzilla.mozilla.org/1319773#c22
+ * [2] https://bugzilla.mozilla.org/1492607
+ * [3] https://developer.mozilla.org/en-US/docs/Web/API/Window/postMessage ***/
+   // user_pref("privacy.firstparty.isolate.restrict_opener_access", true); // [DEFAULT: true]
+   // user_pref("privacy.firstparty.isolate.block_post_message", true);
+/* 4003: enable scheme with FPI [FF78+]
+ * [NOTE] Experimental: existing data and site permissions are incompatible
+ * and some site exceptions may not work e.g. HTTPS-only mode (see 1244) ***/
+   // user_pref("privacy.firstparty.isolate.use_site", true);
+
+/*** [SECTION 4500]: RFP (RESIST FINGERPRINTING)
+   RFP covers a wide range of ongoing fingerprinting solutions.
+   It is an all-or-nothing buy in: you cannot pick and choose what parts you want
+
+   [WARNING] Do NOT use extensions to alter RFP protected metrics
+   [WARNING] Do NOT use prefs in section 4600 with RFP as they can interfere
+
+ FF41+
+    418986 - limit window.screen & CSS media queries leaking identifiable info
+      [TEST] https://arkenfox.github.io/TZP/tzp.html#screen
+ FF50+
+   1281949 - spoof screen orientation
+   1281963 - hide the contents of navigator.plugins and navigator.mimeTypes (FF50+)
+ FF55+
+   1330890 - spoof timezone as UTC 0
+   1360039 - spoof navigator.hardwareConcurrency as 2 (see 4601)
+   1217238 - reduce precision of time exposed by javascript
+ FF56+
+   1369303 - spoof/disable performance API (see 4602, 4603)
+   1333651 - spoof User Agent & Navigator API (see section 4700)
+      JS: FF78+ the version is spoofed as ESR, and the OS as Windows 10, OS 10.15, Android 9 (FF91+ as 10), or Linux
+      HTTP Headers: spoofed as Windows or Android
+   1369319 - disable device sensor API (see 4604)
+   1369357 - disable site specific zoom (see 4605)
+   1337161 - hide gamepads from content (see 4606)
+   1372072 - spoof network information API as "unknown" when dom.netinfo.enabled = true (see 4607)
+   1333641 - reduce fingerprinting in WebSpeech API (see 4608)
+ FF57+
+   1369309 - spoof media statistics (see 4610)
+   1382499 - reduce screen co-ordinate fingerprinting in Touch API (see 4611)
+   1217290 & 1409677 - enable fingerprinting resistance for WebGL (see 2010-12)
+   1382545 - reduce fingerprinting in Animation API
+   1354633 - limit MediaError.message to a whitelist
+   1382533 & 1697680 - enable fingerprinting resistance for Presentation API (FF57-87)
+      This blocks exposure of local IP Addresses via mDNS (Multicast DNS)
+ FF58+
+    967895 - spoof canvas and enable site permission prompt before allowing canvas data extraction
+ FF59+
+   1372073 - spoof/block fingerprinting in MediaDevices API
+      Spoof: enumerate devices reports one "Internal Camera" and one "Internal Microphone" if
+             media.navigator.enabled is true (see 2505 which we chose to keep disabled)
+      Block: suppresses the ondevicechange event (see 4612)
+   1039069 - warn when language prefs are set to non en-US (see 0210, 0211)
+   1222285 & 1433592 - spoof keyboard events and suppress keyboard modifier events
+      Spoofing mimics the content language of the document. Currently it only supports en-US.
+      Modifier events suppressed are SHIFT and both ALT keys. Chrome is not affected.
+ FF60-67
+   1337157 - disable WebGL debug renderer info (see 4613) (FF60+)
+   1459089 - disable OS locale in HTTP Accept-Language headers (ANDROID) (FF62+)
+   1479239 - return "no-preference" with prefers-reduced-motion (see 4614) (FF63+)
+   1363508 - spoof/suppress Pointer Events (see 4615) (FF64+)
+      FF65: pointerEvent.pointerid (1492766)
+   1485266 - disable exposure of system colors to CSS or canvas (see 4616) (FF67+)
+   1407366 - enable inner window letterboxing (see 4504) (FF67+)
+   1494034 - return "light" with prefers-color-scheme (see 4617) (FF67+)
+ FF68-77
+   1564422 - spoof audioContext outputLatency (FF70+)
+   1595823 - spoof audioContext sampleRate (FF72+)
+   1607316 - spoof pointer as coarse and hover as none (ANDROID) (FF74+)
+ FF78+
+   1621433 - randomize canvas (previously FF58+ returned an all-white canvas) (FF78+)
+   1653987 - limit font visibility to bundled and "Base Fonts" (see 4618) (Windows, Mac, some Linux) (FF80+)
+   1461454 - spoof smooth=true and powerEfficient=false for supported media in MediaCapabilities (FF82+)
+***/
+user_pref("_user.js.parrot", "4500 syntax error: the parrot's popped 'is clogs");
+/* 4501: enable privacy.resistFingerprinting [FF41+]
+ * This pref is the master switch for all other privacy.resist* prefs unless stated
+ * [SETUP-WEB] RFP can cause the odd website to break in strange ways, and has a few side affects,
+ * but is largely robust nowadays. Give it a try. Your choice. Also see 4504 (letterboxing).
+ * [1] https://bugzilla.mozilla.org/418986 ***/
+user_pref("privacy.resistFingerprinting", true);
+/* 4502: set new window sizes to round to hundreds [FF55+] [SETUP-CHROME]
+ * Width will round down to multiples of 200s and height to 100s, to fit your screen.
+ * The override values are a starting point to round from if you want some control
+ * [1] https://bugzilla.mozilla.org/1330882 ***/
+   // user_pref("privacy.window.maxInnerWidth", 1000);
+   // user_pref("privacy.window.maxInnerHeight", 1000);
+/* 4503: disable mozAddonManager Web API [FF57+]
+ * [NOTE] To allow extensions to work on AMO, you also need 2662
+ * [1] https://bugzilla.mozilla.org/buglist.cgi?bug_id=1384330,1406795,1415644,1453988 ***/
+user_pref("privacy.resistFingerprinting.block_mozAddonManager", true); // [HIDDEN PREF]
+/* 4504: enable RFP letterboxing [FF67+]
+ * Dynamically resizes the inner window by applying margins in stepped ranges [2]
+ * If you use the dimension pref, then it will only apply those resolutions. The format is
+ * "width1xheight1, width2xheight2, ..." (e.g. "800x600, 1000x1000, 1600x900")
+ * [SETUP-WEB] This does NOT require RFP (see 4501) **for now**, so if you're not using 4501, or you are but
+ * dislike margins being applied, then flip this pref, keeping in mind that it is effectively fingerprintable
+ * [WARNING] The dimension pref is only meant for testing, and we recommend you DO NOT USE it
+ * [1] https://bugzilla.mozilla.org/1407366
+ * [2] https://hg.mozilla.org/mozilla-central/rev/6d2d7856e468#l2.32 ***/
+user_pref("privacy.resistFingerprinting.letterboxing", true); // [HIDDEN PREF]
+   // user_pref("privacy.resistFingerprinting.letterboxing.dimensions", ""); // [HIDDEN PREF]
+/* 4510: disable showing about:blank as soon as possible during startup [FF60+]
+ * When default true this no longer masks the RFP chrome resizing activity
+ * [1] https://bugzilla.mozilla.org/1448423 ***/
+user_pref("browser.startup.blankWindow", false);
+/* 4520: disable chrome animations [FF77+] [RESTART]
+ * [NOTE] pref added in FF63, but applied to chrome in FF77. RFP spoofs this for web content ***/
+user_pref("ui.prefersReducedMotion", 1); // [HIDDEN PREF]
+
+/*** [SECTION 4600]: RFP ALTERNATIVES
+     [WARNING] Do NOT use prefs in this section with RFP as they can interfere
+***/
+user_pref("_user.js.parrot", "4600 syntax error: the parrot's crossed the Jordan");
+/* [SETUP-non-RFP] Non-RFP users replace the * with a slash on this line to enable these
+// FF55+
+// 4601: [2514] spoof number of CPU cores [FF48+]
+   // [1] https://bugzilla.mozilla.org/1008453
+   // [2] https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/21675
+   // [3] https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/22127
+   // [4] https://html.spec.whatwg.org/multipage/workers.html#navigator.hardwareconcurrency
+user_pref("dom.maxHardwareConcurrency", 2);
+// FF56+
+// 4602: [2411] disable resource/navigation timing
+user_pref("dom.enable_resource_timing", false);
+// 4603: [2412] disable timing attacks
+   // [1] https://wiki.mozilla.org/Security/Reviews/Firefox/NavigationTimingAPI
+   // user_pref("dom.enable_performance", false);
+// 4604: [2512] disable device sensor API
+   // Optional protection depending on your device
+   // [1] https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/15758
+   // [2] https://blog.lukaszolejnik.com/stealing-sensitive-browser-data-with-the-w3c-ambient-light-sensor-api/
+   // [3] https://bugzilla.mozilla.org/buglist.cgi?bug_id=1357733,1292751
+   // user_pref("device.sensors.enabled", false);
+// 4605: [2515] disable site specific zoom
+   // Zoom levels affect screen res and are highly fingerprintable. This does not stop you using
+   // zoom, it will just not use/remember any site specific settings. Zoom levels on new tabs
+   // and new windows are reset to default and only the current tab retains the current zoom
+user_pref("browser.zoom.siteSpecific", false);
+// 4606: [2501] disable gamepad API - USB device ID enumeration
+   // Optional protection depending on your connected devices
+   // [1] https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/13023
+   // user_pref("dom.gamepad.enabled", false);
+// 4607: [2503] disable giving away network info [FF31+]
+   // e.g. bluetooth, cellular, ethernet, wifi, wimax, other, mixed, unknown, none
+   // [1] https://developer.mozilla.org/docs/Web/API/Network_Information_API
+   // [2] https://wicg.github.io/netinfo/
+   // [3] https://bugzilla.mozilla.org/960426
+user_pref("dom.netinfo.enabled", false); // [DEFAULT: true on Android]
+// 4608: [2021] disable the SpeechSynthesis (Text-to-Speech) part of the Web Speech API
+   // [1] https://developer.mozilla.org/docs/Web/API/Web_Speech_API
+   // [2] https://developer.mozilla.org/docs/Web/API/SpeechSynthesis
+   // [3] https://wiki.mozilla.org/HTML5_Speech_API
+user_pref("media.webspeech.synth.enabled", false);
+// FF57+
+// 4610: [2506] disable video statistics - JS performance fingerprinting [FF25+]
+   // [1] https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/15757
+   // [2] https://bugzilla.mozilla.org/654550
+user_pref("media.video_stats.enabled", false);
+// 4611: [2509] disable touch events
+   // fingerprinting attack vector - leaks screen res & actual screen coordinates
+   // 0=disabled, 1=enabled, 2=autodetect
+   // Optional protection depending on your device
+   // [1] https://developer.mozilla.org/docs/Web/API/Touch_events
+   // [2] https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/10286
+   // user_pref("dom.w3c_touch_events.enabled", 0);
+// FF59+
+// 4612: [2511] disable MediaDevices change detection [FF51+]
+   // [1] https://developer.mozilla.org/docs/Web/Events/devicechange
+   // [2] https://developer.mozilla.org/docs/Web/API/MediaDevices/ondevicechange
+user_pref("media.ondevicechange.enabled", false);
+// FF60+
+// 4613: [2011] disable WebGL debug info being available to websites
+   // [1] https://bugzilla.mozilla.org/1171228
+   // [2] https://developer.mozilla.org/docs/Web/API/WEBGL_debug_renderer_info
+user_pref("webgl.enable-debug-renderer-info", false);
+// FF63+
+// 4614: enforce prefers-reduced-motion as no-preference [FF63+] [RESTART]
+   // 0=no-preference, 1=reduce
+user_pref("ui.prefersReducedMotion", 0); // [HIDDEN PREF]
+// FF64+
+// 4615: [2516] disable PointerEvents [FF86 or lower]
+   // [1] https://developer.mozilla.org/en-US/docs/Web/API/PointerEvent
+   // [-] https://bugzilla.mozilla.org/1688105
+user_pref("dom.w3c_pointer_events.enabled", false);
+// FF67+
+// 4616: [2618] disable exposure of system colors to CSS or canvas [FF44+]
+   // [NOTE] See second listed bug: may cause black on black for elements with undefined colors
+   // [SETUP-CHROME] Might affect CSS in themes and extensions
+   // [1] https://bugzilla.mozilla.org/buglist.cgi?bug_id=232227,1330876
+user_pref("ui.use_standins_for_native_colors", true);
+// 4617: enforce prefers-color-scheme as light [FF67+]
+   // 0=light, 1=dark : This overrides your OS value
+user_pref("ui.systemUsesDarkTheme", 0); // [HIDDEN PREF]
+// FF80+
+// 4618: limit font visibility (non-ANDROID) [FF79+]
+   // Uses hardcoded lists with two parts: kBaseFonts + kLangPackFonts [1]
+   // 1=only base system fonts, 2=also fonts from optional language packs, 3=also user-installed fonts
+   // [NOTE] Bundled fonts are auto-allowed
+   // [1] https://searchfox.org/mozilla-central/search?path=StandardFonts*.inc
+user_pref("layout.css.font-visibility.level", 1);
+// ***/
+
+/*** [SECTION 4700]: RFP ALTERNATIVES (USER AGENT SPOOFING)
+     These prefs are insufficient and leak. Use RFP and **nothing else**
+     - Many of the user agent components can be derived by other means. When those
+       values differ, you provide more bits and raise entropy. Examples include
+       workers, iframes, headers, tcp/ip attributes, feature detection, and many more
+     - Web extensions also lack APIs to fully protect spoofing
+***/
+user_pref("_user.js.parrot", "4700 syntax error: the parrot's taken 'is last bow");
+/* 4701: navigator DOM object overrides
+ * [WARNING] DO NOT USE ***/
+   // user_pref("general.appname.override", ""); // [HIDDEN PREF]
+   // user_pref("general.appversion.override", ""); // [HIDDEN PREF]
+   // user_pref("general.buildID.override", ""); // [HIDDEN PREF]
+   // user_pref("general.oscpu.override", ""); // [HIDDEN PREF]
+   // user_pref("general.platform.override", ""); // [HIDDEN PREF]
+   // user_pref("general.useragent.override", ""); // [HIDDEN PREF]
+
+/*** [SECTION 5000]: PERSONAL
+     Non-project related but useful. If any of these interest you, add them to your overrides
+     To save some overrides, we've made a few active as they seem to be universally used ***/
+user_pref("_user.js.parrot", "5000 syntax error: this is an ex-parrot!");
+/* WELCOME & WHAT's NEW NOTICES ***/
+user_pref("browser.startup.homepage_override.mstone", "ignore"); // master switch
+   // user_pref("startup.homepage_welcome_url", "");
+   // user_pref("startup.homepage_welcome_url.additional", "");
+   // user_pref("startup.homepage_override_url", ""); // What's New page after updates
+/* WARNINGS ***/
+   // user_pref("browser.tabs.warnOnClose", false);
+   // user_pref("browser.tabs.warnOnCloseOtherTabs", false);
+   // user_pref("browser.tabs.warnOnOpen", false);
+   // user_pref("full-screen-api.warning.delay", 0);
+   // user_pref("full-screen-api.warning.timeout", 0);
+/* APPEARANCE ***/
+   // user_pref("browser.download.autohideButton", false); // [FF57+]
+   // user_pref("toolkit.legacyUserProfileCustomizations.stylesheets", true); // [FF68+] allow userChrome/userContent
+/* CONTENT BEHAVIOR ***/
+   // user_pref("accessibility.typeaheadfind", true); // enable "Find As You Type"
+   // user_pref("clipboard.autocopy", false); // disable autocopy default [LINUX]
+   // user_pref("layout.spellcheckDefault", 2); // 0=none, 1-multi-line, 2=multi-line & single-line
+/* UX BEHAVIOR ***/
+   // user_pref("browser.backspace_action", 2); // 0=previous page, 1=scroll up, 2=do nothing
+   // user_pref("browser.quitShortcut.disabled", true); // disable Ctrl-Q quit shortcut [LINUX] [MAC] [FF87+]
+   // user_pref("browser.tabs.closeWindowWithLastTab", false);
+   // user_pref("browser.tabs.loadBookmarksInTabs", true); // open bookmarks in a new tab [FF57+]
+   // user_pref("browser.urlbar.decodeURLsOnCopy", true); // see bugzilla 1320061 [FF53+]
+   // user_pref("general.autoScroll", false); // middle-click enabling auto-scrolling [DEFAULT: false on Linux]
+   // user_pref("ui.key.menuAccessKey", 0); // disable alt key toggling the menu bar [RESTART]
+   // user_pref("view_source.tab", false); // view "page/selection source" in a new window [FF68+, FF59 and under]
+/* UX FEATURES: disable and hide the icons and menus ***/
+user_pref("browser.messaging-system.whatsNewPanel.enabled", false); // What's New toolbar icon [FF69+]
+   // user_pref("extensions.pocket.enabled", false); // Pocket Account [FF46+]
+   // user_pref("identity.fxaccounts.enabled", false); // Firefox Accounts & Sync [FF60+] [RESTART]
+   // user_pref("reader.parse-on-load.enabled", false); // Reader View
+/* OTHER ***/
+   // user_pref("browser.bookmarks.max_backups", 2);
+user_pref("browser.newtabpage.activity-stream.asrouter.userprefs.cfr.addons", false); // disable CFR [FF67+]
+      // [SETTING] General>Browsing>Recommend extensions as you browse
+user_pref("browser.newtabpage.activity-stream.asrouter.userprefs.cfr.features", false); // disable CFR [FF67+]
+      // [SETTING] General>Browsing>Recommend features as you browse
+   // user_pref("network.manage-offline-status", false); // see bugzilla 620472
+   // user_pref("xpinstall.signatures.required", false); // enforced extension signing (Nightly/ESR)
+
+/*** [SECTION 9999]: DEPRECATED / REMOVED / LEGACY / RENAMED
+     Documentation denoted as [-]. Items deprecated in FF78 or earlier have been archived at [1],
+     which also provides a link-clickable, viewer-friendly version of the deprecated bugzilla tickets
+     [1] https://github.com/arkenfox/user.js/issues/123
+***/
+user_pref("_user.js.parrot", "9999 syntax error: the parrot's deprecated!");
+/* ESR78.x still uses all the following prefs
+// [NOTE] replace the * with a slash in the line above to re-enable them
+// FF79
+// 0212: enforce fallback text encoding to match en-US
+   // When the content or server doesn't declare a charset the browser will
+   // fallback to the "Current locale" based on your application language
+   // [TEST] https://hsivonen.com/test/moz/check-charset.htm
+   // [1] https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/20025
+   // [-] https://bugzilla.mozilla.org/1603712
+user_pref("intl.charset.fallback.override", "windows-1252");
+// FF82
+// 0206: disable geographically specific results/search engines e.g. "browser.search.*.US"
+   // i.e. ignore all of Mozilla's various search engines in multiple locales
+   // [-] https://bugzilla.mozilla.org/1619926
+user_pref("browser.search.geoSpecificDefaults", false);
+user_pref("browser.search.geoSpecificDefaults.url", "");
+// FF86
+// 1205: disable SSL Error Reporting
+   // [1] https://firefox-source-docs.mozilla.org/browser/base/sslerrorreport/preferences.html
+   // [-] https://bugzilla.mozilla.org/1681839
+user_pref("security.ssl.errorReporting.automatic", false);
+user_pref("security.ssl.errorReporting.enabled", false);
+user_pref("security.ssl.errorReporting.url", "");
+// 2653: disable hiding mime types (Options>General>Applications) not associated with a plugin
+   // [-] https://bugzilla.mozilla.org/1581678
+user_pref("browser.download.hide_plugins_without_extensions", false);
+// FF87
+// 0105d: disable Activity Stream recent Highlights in the Library [FF57+]
+   // [-] https://bugzilla.mozilla.org/1689405
+   // user_pref("browser.library.activity-stream.enabled", false);
+// FF89
+// 0309: disable sending Flash crash reports
+   // [-] https://bugzilla.mozilla.org/1682030 [underlying NPAPI code removed]
+user_pref("dom.ipc.plugins.flash.subprocess.crashreporter.enabled", false);
+// 0310: disable sending the URL of the website where a plugin crashed
+   // [-] https://bugzilla.mozilla.org/1682030 [underlying NPAPI code removed]
+user_pref("dom.ipc.plugins.reportCrashURL", false);
+// 1243: block unencrypted requests from Flash on encrypted pages to mitigate MitM attacks [FF59+]
+   // [1] https://bugzilla.mozilla.org/1190623
+   // [-] https://bugzilla.mozilla.org/1682030 [underlying NPAPI code removed]
+user_pref("security.mixed_content.block_object_subrequest", true);
+// 1803: disable Flash plugin
+  // 0=deactivated, 1=ask, 2=enabled
+  // ESR52.x is the last branch to *fully* support NPAPI, FF52+ stable only supports Flash
+  // [NOTE] You can still override individual sites via site permissions
+  // [-] https://bugzilla.mozilla.org/1682030 [underlying NPAPI code removed]
+user_pref("plugin.state.flash", 0); // [DEFAULT: 1]
+// ***/
+
+/* END: internal custom pref to test for syntax errors ***/
+user_pref("_user.js.parrot", "SUCCESS: No no he's not dead, he's, he's restin'!");