I use Tor for internet banking and such. It comes bundled with a browser that's basically Firefox. To update (or install) Tor, you just unpack the download and run some file inside the directory, that is, it's entirely self-contained.
Even though I hardly use it, I like to tweak it a bit, with Pentadactyl and probably Adblock.I'm not sure if these go in the "profile".
My question is, where does Firefox keep such customisations? That way, I could just copy a directory or two rather than setting everything up each time I update. It's presumably important to do every update, too, for security reasons.
I'm pretty sure this question's come up on this forum, but I couldn't find the answer here or on Mozilla'a own site - the information must be out there, but it is swamped by vaguely related stuff.