Includes handy things like
- find which package contains
apt-file search empheq.sty
To remap the left and right arrow of Lacra's pointer to the down and right arrows, respectively, did
xmodmap -e "keycode 117 = Right"
xmodmap -e "keycode 112 = Down"
found the keycodes useing
xev. This list of symbol names may be useful: