My wife had outpatient surgery recently, which involved a nerve block in one shoulder, deadening her arm for the rest of the day. Surprisingly (to me) that was plenty of time to develop phantom limb syndrome, where it feels like there's an invisible arm in place of the real one, that you can't control, and that gets agonizingly knotted and cramped. Vilayanur Ramachandran invented the "mirror box" treatment, where a mirror is held vertically in front of you, perpendicular to your body and between your resting hands. Your good hand is visible only in the mirror, so its image looks like it is the other hand, and that is enough to allow you to control the phantom limb. It worked.
Running firefox under gdb takes a few steps. You will need the debug symbols, e.g "apt-get install iceweasel-dbg". In gdb,
(gdb) file /usr/lib/iceweasel/firefox-bin
(gdb) handle SIGPIPE noprint nostop
(gdb) maint info sections
(gdb) add-symbol-file /usr/lib/debug/usr/lib/iceweasel/components/libbrowsercomps.so 0x8049480
The number 0x8049480 above is the first number in the line of output from "main info sections" that contains ".text", and varies from one build to the next.