How To Optimize Firefox By Tweaking Hidden Settings In The "about:config" Page
v.68 about:config settings could be altered to allow local testing; v.69 seems to have more and different settings to change: can you advise please? | Firefox Support Forum | Mozilla Support
Tip] How to Access Hidden Secret “About:Config” Editor Page in Mozilla Thunderbird – AskVG
Customize Privacy Settings in Mozilla Firefox: Part 1 (about:config) | WebDevelopmentAid