about:config

FYI. This is a user help page for most recent support browser or esr and what your asking isn't what user on here would do or have time as such. You should do a search for this online.

Which Firefox forks or versions of Firefox support about:config tweaking. List ALL. THANKS

The about:config should work in current versions. The whole idea of about:config tweaks has not been discussed much in the last decade like it used to be in the first decade of the web browser existence.