Firefox

ExtensionsConfigurationSourceForumsAlternatives

Extensions

GitHub uMatrix filters net requests. Development has ended.

GitHub uBlocko is a general-purpose blocker.

GitHub CanvasBlocker blocks canvas-API to prevent canvas fingerprinting.

AMO CSS Exfil Protection sanitizes and blocks any CSS rules which may be designed to steal data. GitHub Source

AMO LocalCDN emulates remote frameworks (e.g. jQuery, Bootstrap, AngularJS) and delivers them as local resource. Codeberg Source

AMO Neat URL removes garbage from URLs. GitHub Source

AMO Privacy Possum wrenches common commercial tracking methods by reducing and falsifying the data gathered by tracking companies. GitHub Source

AMO Print Edit WE helps to choose the contents of a web page prior to printing.

AMO Feedbro is advanced feed reader (RSS, Atom, RDF) with built-in social media plugin support (Youtube, Facebook, Twitter, Instagram and etc.).

AMO Markdown Viewer Webext is Markdown (.md) file viewer. GitHub Source, Note for Linux users

Extensions - arkenfox Wiki

Configuration

The large number of browser settings can be configured via user.js. For the desktops, create your user.js somewhere and drop it into your Profile directory. The apply user.js in unrooted Android is more difficult (see, arkenfox Wiki).

Comprehensive user.js template for configuring and hardening Firefox - arkenfox

Firefox Configuration Guide for Privacy Freaks and Performance Buffs - 12bytes.org

Descriptions of some Firefox settings - DonQuixoteI

Privacy-Handbuch - privacy-handbuch.de (in German)

Firefox Tuning zur Absicherung und Anonymisierung - kairaven.de (in German)

A brief guide to Mozilla preferences - MDN

Bugzilla/Release/Source

Bugzilla

Firefox Releases for Desktop

Release Calendar

Searchfox is a source code indexing tool for Mozilla Firefox

Nightly Firefox source code search tool (DXR)

Forums

mozillaZine Forums

Firefox Builds - mozillaZine Forums

Alternatives

Chromium

Palemoon