# 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](https://firefox-ci-tc.services.mozilla.com/tasks/index/mobile.v2.fenix.nightly.latest) - Mozilla-mobile
* [Iceraven browser](https://github.com/fork-maintainers/iceraven-browser) - Forks maintainers
* [Fennec F-Droid](https://f-droid.org/en/packages/org.mozilla.fennec_fdroid/) - F-Droid
* [Mull](https://f-droid.org/en/packages/us.spotco.fennec_dos/) - F-Droid

If you are running IcecatMobile or old Fennec (version 68) use [Quindecim user.js](https://git.nixnet.xyz/quindecim/mobile_user.js) instead.



## How to install (only rooted devices)


I would like to suggest the use of [Amaze](https://github.com/TeamAmaze/AmazeFileManager) or [TWRP File Manager](https://twrp.me/Devices/) 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](https://gitlab.com/relan/fennecbuild/-/merge_requests/40)

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](https://github.com/arkenfox/user.js) - The majority of this user.js.
* [Tor Project](https://www.torproject.org) - Some Tor Browser strings.
* [Quindecim](https://git.nixnet.xyz/quindecim/mobile_user.js) - Initial releases, unique strings and user design.
* [LibreWolf](https://gitlab.com/librewolf-community) - Some strings.
* [Better-Fox](https://github.com/yokoffing/Better-Fox) - Some strings
* [gallegonovato](https://git.nixnet.xyz/gallegonovato) - For his suggestions and support.
* [v1nc](https://github.com/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