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](https://github.com/arkenfox/user.js/wiki/2.1-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).
Everyone, experts included, should at least read the [wiki](https://github.com/arkenfox/user.js/wiki), as it contains important information regarding a few `user.js` settings.
Note that we do *not* recommend connecting over Tor on Firefox. Use the [Tor Browser](https://www.torproject.org/projects/torbrowser.html.en) if your [threat model](https://2019.www.torproject.org/about/torusers.html) 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.