user.js is a configuration file that can control hundreds of Firefox settings. For a more technical breakdown and explanation, you can read more on the overview wiki page.
ghacks user.js is a template, which, as provided, 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 implementation wiki page, as it contains important information regarding a few
ghacks user.js settings.
Literally thousands of sources, references and suggestions. That said...
- Martin Brinkmann at ghacks 1
- The ghacks community and commentators
- The 12bytes article now uses this user.js and supplements it with an additonal JS hosted at GitLab
1 The ghacks user.js was an independent project by Thorin-Oakenpants started in early 2015 and was first published at ghacks in August 2015. With Martin Brinkmann's blessing, it will keep the ghacks name.