X » Get symbolic names for keycodes
xmodmap can print out its current keymap including symbolic names:
xmodmap -pke
Which gives output like:
keycode 171 = XF86AudioNext NoSymbol XF86AudioNext
keycode 172 = XF86AudioPlay XF86AudioPause XF86AudioPlay XF86AudioPause
keycode 173 = XF86AudioPrev NoSymbol XF86AudioPrev
keycode 174 = XF86AudioStop XF86Eject XF86AudioStop XF86Eject