user.js | Firefox Fenix Nightly, Iceraven, Fennec F-Droid and Mull

The user.js file is used to configure Firefox for android in the safest and fastest way possible.

Goals:

• enhance security and privacy
• improve performance
• better fingerprint possible
• reduce automatic connections

Compatible browsers:

This user.js has been designed for mobile purposes and you can use it on these browsers:

• Firefox Fenix Nightly for Android - Mozilla-mobile
• Iceraven browser - Forks maintainers
• Fennec F-Droid - F-Droid
• Mull - F-Droid

If you are running IcecatMobile or old Fennec (version 68) use Quindecim user.js instead.

How to install (only rooted devices)

I would like to suggest the use of Amaze or TWRP File Manager before proceed. As for the first one, make sure you enable "Use legacy listing for root" in Settings/Behavior/Advanced.

• Download and install the browsers from their official websites (see above)

• Start the browser for the first time (offline mode/no data connections) and wait about 5 sec.

• Close it.

• Clone or download zip file and extract it

• Locate browser's installation directory similar to this:

  ✳️ Firefox Fenix Nightly data/data/org.mozilla.fenix/files/mozilla/[xxxxxxx].default

  ✳️ Iceraven data/data/io.github.forkmaintainers.iceraven/files/mozilla/[xxxxxxx].default

  ✳️ Fennec F-Droid data/data/org.mozilla.fennec_froid/files/mozilla/[xxxxxxx].default

  ✳️ Mull data/data/us.spotco.fennec_dos/files/mozilla/[xxxxxxx].default

• Copy the extracted user.js file to the above installation directory. If you are using Amaze, once the file is copied, tap the three dots, properties/permissions and enable all the "read" ones and "write" for owner and group. Finally, tap Set and Ok.

• Delete prefs.js file inside the above directory

• Start the browser and test if user.js was applied : browse to about:config and look if _config.is.applied is true.

Installing Iceraven addons in Fennec/Mull/Firefox Nightly

First of all, take into account automatic addons updates are blocked in order to avoid all the Mozilla connections.

Go to Settings, about Fennec/Mull/Firefox Nightly, tap 5 times over its logo, Debug mode will enable.

Back to Settings, Install add-on from file and select your .xpi files.

Anyway, if you wish automatic updates, edit these files adding // this way -> user_pref -> // user_pref

user_pref("extensions.update.enabled", false);

user_pref("extensions.update.url", "");

user_pref("extensions.autoupdate.enabled", false);

user_pref("extensions.update.background.url", "");

user_pref("extensions.update.autoUpdateDefault", false);

Considerations

Once installed, go to Settings, ETP and select Strict.

Some automatic connections could not be blocked so you will have to add them to your host list.

firefox.settings.services.mozilla.com

https://bugzilla.mozilla.org/show_bug.cgi?id=1598562#c13

gitlab.com (Fennec), in order to install wallpapers

safebrowsing.googleapis.com, safebrowsing.google.com, malware-error.mozilla.com, phish-error.mozilla.com and developers.google.com (safebrowsing is active and not changeable)

https://github.com/mozilla-mobile/fenix/issues/14163

Known problems

Some breakage?

Try changing "network.http.referer.XOriginPolicy" from 2 to 1

Performance loss?

You have to change these strings from false to true:

javascript.options.ion

javascript.options.baselinejit

javascript.options.native_regexp

Bugs with HTTP sites?

Due to fission is enabled, HTTP websites don't load when HTTPS only mode is activated . Consider disabling it. There are also issues with self signed certificates in HTTPS webs.

Thanks

I really thank the following authors:

• Arkenfox - The majority of this user.js.
• Tor Project - Some Tor Browser strings.
• Quindecim - Initial releases, unique strings and user design.
• LibreWolf - Some strings.
• Better-Fox - Some strings
• gallegonovato - For his suggestions and support.
• v1nc - For his user.js updater app.

License

GNU General Public License v3.0.

See LICENSE for more details.

Other mirrors

https://codeberg.org/Narsil/user.js/src/branch/main/mobile