More information: Librewolf
Librewolf is a fork of Firefox focusing on goals of "privacy, security, and user freedom." It comes with an extensive list of (refer to the Arkenfox project) privacy tweaks by default. Private search providers, such as DuckDuckGo, are included by default.
Librewolf also disables telemetry enabled by vanilla Firefox by default. It also disables digital rights management (DRM) features, which may make playing back video/streaming content from specific providers difficult.
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avoidthehack Recommendation status: Recommended (Windows | Linux/macOS)
Librewolf can be installed in many ways, depending on user choice and user operating system: Install Guide
Note: This guide is deprecated, but could still serve as a reference for those interested in getting started with Librewolf.