Firefox is a supremely configurable browser with an array of useful settings, but many are so deeply buried in about:config that you may never even realize they exist.
ConfigFox is a free portable tool for Windows which makes it easier to view and manage Firefox’s more advanced privacy and security-related options.
The program first acts as a GUI for your settings, presenting them in a tree with the following categories: Startup, Auto Updates, Privacy, Location bar/ search/ auto suggestions/ history, Cache, SSL/ OCSP/ Certs/ Encryption/ http, Plugins, Media/ Camera/ Mic, JavaScript & DOM, Leaks/ fingerprinting/ security/ dev tools, and Tweaks.
Expanding any category gives you a list of possible options, and expanding these shows you the name of the official Firefox setting (so the program’s "Disable browser auto update" directly relates to the Firefox setting app.update.enabled).
Every category and setting has a checkbox you can use to enable or disable it.
Most options are fairly obvious ("Disable camera"), but others do require some background knowledge ("Enable OCSP Stapling").
If you’re unsure what something means, right-click the relevant Firefox setting, select Search Online and a web browser window opens with any matches.
Once you’re finished, the Save option saves your new settings to a Users.js file in your user profile (it won’t open an existing Users.js, so if you have one already then we’d back that up first). Restart Firefox and the new settings should be applied.
A File > Get Latest Configurations options updates the program with any new Firefox settings.
Alternatively, if you know what you’re doing you can customize ConfigFox yourself. Right-clicking any setting displays options to delete or edit it, and you can freely add new settings or groups to suit your needs.
ConfigFox needs to be treated with care, as a poorly-chosen tweak could cause all kinds of problems. If in doubt, back up your profile first (the program has a Tools menu option to do this for you).
The package does make it easier to view and manage your settings, though, and if you’re interested in advanced Firefox tweakery then it deserves a closer look.