[I have quit wow. It is unlikely I will update this, or any other of my addons.
If you wish to take them over, feel free.
When you mouse over a character or creature in the game that is currently targeting something, it shows a second, small tooltip attached to the main tooltip with their target's name, level, and other info.
toggle - toggle show / hide
on - show
off - hide
red - toggle turning the background of the second tooltip red if the target is the player
green - toggle making the second tooltip green if you are targeting the same the target
pos # (1-12) - relocate the second tooltip around the gametooltip.