Firefox for Android, built from Mozilla's official source by F-Droid — with the proprietary bits removed.
Firefox built from source without telemetry or Play integration. Requests standard browser permissions; tracking protection is on by default.
Fennec F-Droid is the Firefox mobile browser built from Mozilla's source with proprietary components (telemetry keys, Play Services integration, bundled codecs licensing) removed or replaced. What you get is the real Gecko engine with full web compatibility, add-on support, and Firefox Sync if you want it. As a browser it brings Enhanced Tracking Protection, per-site permissions, reader mode, and the full extension ecosystem — uBlock Origin and friends install from the add-ons collection. Sync is optional: without it, the browser keeps everything on-device. Releases track Firefox for Android. The F-Droid build is the choice when you want the engine without the wrapper.
Fennec F-Droid by Mozilla / F-Droid — Tools app, 90 MB, requires Android 5.0+. Direct APK download on AppsDone, scanned for malware.