user.js
Firefox privacy, security and anti-tracking: a comprehensive user.js
...Everyone, experts included, should at least read the 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 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.