https://github.com/arkenfox/user.js/blob/master/user.js and search for [HIDDEN PREF]
In Anti-fingerprinting extensions tend to make fingerprinting easierarkenfox
user.js
JavaScript2018–2026
arkenfox / user.js
user.js
Firefox privacy, security and anti-tracking: a comprehensive user.js template for configuration and hardening
78Distinct people
110Mentions
5Explicit recommenders
13KGitHub stars
What to know before exploring
What it is
Firefox privacy, security and anti-tracking: a comprehensive user.js template for configuration and hardening
GitHub
Where it is used
No documented product use was verified in the last source check.
What people are saying
For extensions, I recommend people follow the recommendations[1] in the arkenfox repo and either harden their firefox or use librewolf. Umatrix is unmaintained since 2019. [1]…
bmikaili used a recommendation phrase. 5 indexed comments match. This is a phrase match, not a verdict.
No classified warning is attached to this page. Read the discussions before treating silence as approval.
Also in these discussions
- pyllyukko/user.js · linked in 3 of the same discussions
- yokoffing/betterfox · linked in 3 of the same discussions
Mentioned in the same Hacker News threads. That is not proof they are substitutes.
This week on Hacker News
Nov 8–Nov 15 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/15/2026, 10:56:20 AM UTC.
No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.
Mentions over time
HN mentions by year110 dated mentions
Observed mentions: 2018-09-14 13:37:15 UTC to 2026-03-07 01:03:43 UTC.
* An incomplete calendar period is marked with an outlined bar. Its count is not directly comparable with a full period.
Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.
View mention counts and date ranges
| Period | Start (UTC) | End (exclusive, UTC) | Mentions | Submissions | Comments |
|---|---|---|---|---|---|
| 2018 | 2018-01-01 00:00:00 UTC | 2019-01-01 00:00:00 UTC | 1 | 0 | 1 |
| 2019 | 2019-01-01 00:00:00 UTC | 2020-01-01 00:00:00 UTC | 13 | 1 | 12 |
| 2020 | 2020-01-01 00:00:00 UTC | 2021-01-01 00:00:00 UTC | 8 | 0 | 8 |
| 2021 | 2021-01-01 00:00:00 UTC | 2022-01-01 00:00:00 UTC | 11 | 1 | 10 |
| 2022 | 2022-01-01 00:00:00 UTC | 2023-01-01 00:00:00 UTC | 25 | 1 | 24 |
| 2023 | 2023-01-01 00:00:00 UTC | 2024-01-01 00:00:00 UTC | 20 | 0 | 20 |
| 2024 | 2024-01-01 00:00:00 UTC | 2025-01-01 00:00:00 UTC | 10 | 1 | 9 |
| 2025 | 2025-01-01 00:00:00 UTC | 2026-01-01 00:00:00 UTC | 20 | 0 | 20 |
| 2026 (partial) | 2026-01-01 00:00:00 UTC | 2027-01-01 00:00:00 UTC | 2 | 0 | 2 |
From the project README
An excerpt from the repository, fetched Nov 13, 2026.
Read the project’s introduction
This repo and the interactive webpage linked below are the only official sources - do not trust any other sites claiming to be Arkenfox
🟪 user.js
A user.js is a configuration file that can control Firefox settings - for a more technical breakdown and explanation, you can read more in the wiki
🟩 the arkenfox user.js
The arkenfox user.js is a template which aims to provide as much privacy and enhanced security as possible, and to reduce tracking and fingerprinting as much as possible - while minimizing any loss of functionality and breakage (but it will happen).
Firefox's built-in profile feature (enabled since FF150) can copy some preferences across profiles, including data-reporting and Health Reports preferences set by this template. Do not assume these settings are independent per profile; review Permissions and data > Firefox data collection and use in Firefox Settings and verify the shared behavior. The exact shared-preference list is Firefox-version-dependent. See 1933264 and permanentSharedPrefs.
Everyone, experts included, should at least read the wiki, as it contains important information regarding a few user.js settings. There is also an interactive current release, thanks to icpantsparti2.
Note that we do not recommend connecting over Tor on Firefox. Use the Tor Browser if your threat model calls for it, or for accessing hidden services.
Also be aware that the arkenfox user.js is made specifically for desktop Firefox. Using it as-is in other Gecko-based browsers can be counterproductive, especially in the Tor Browser.
🟧 sitemap
releases
changelogs
wiki
stickies
diffs
common questions and answers
🟥 acknowledgments
Literally thousands of sources, references and suggestions. Many thanks, and much appreciated.
Read the full README on GitHubWhat Hacker News says
8 sourcesI’m afraid their fingerprint randomizing methods may be doing more harm then good.
https://github.com/arkenfox/user.js/wiki/4.1-Extensions#smal...
In Cover Your TracksRandomizing fingerprints is generally a bad idea. See:
https://github.com/arkenfox/user.js/wiki/4.1-Extensions#smal...
In Cover Your Tracks> “Add-ons and browsers that randomize the results of fingerprinting metrics have the potential to confuse trackers and mitigate the effects of fingerprinting as a method of tracking.”
I would like to dispute this. It is easy to detect when a user is spoofing certain settings. As such, randomizing fingerprint data increases entropy, making your browser more unique, not less. There is a reason why the Tor browser works so hard to make sure every user has the same fingerprint, rather than randomizing it.
More on that here: https://github.com/arkenfox/user.js/wiki/4.1-Extensions#smal...
In Cover Your Trackshttps://github.com/arkenfox/user.js
is militantly maintained.
It documents and make it easy to use many of the features upstreamed into Firefox by the Tor Project.
In Cover Your TracksPreviously I had managed to force Firefox not to make unwanted automatic connections using gHacks user.js [0] and this official guide [1], but this new version makes a connection to firefox.settings.services.mozilla.com after startup no matter what. Not a big deal, but leaves a bad aftertaste from the upgrade.
[0] https://github.com/ghacksuserjs/ghacks-user.js
[1] https://support.mozilla.org/en-US/kb/how-stop-firefox-making...
In Firefox 73Just saw this today:
An ongoing comprehensive user.js template for configuring and hardening Firefox privacy, security and anti-fingerprinting
https://github.com/ghacksuserjs/ghacks-user.js
In Ask HN: How to Prevent Website(s) from Fingerprinting?I am using ghacks user.js[1], which makes fingerprinting harder and improves my privacy online. Removing user.js would mean less privacy for me.
[1]: https://github.com/ghacksuserjs/ghacks-user.js
In Firefox considering off-by-default preference for loading user.js files