If you're on multiplayer, you can use the camera angle on your opponent perpective (press 6 or 7 hotkey) and then "control" the body.
You won't see his joint states but you can move all his joints with scroll, just put your mouse cursor on it and then use scroll.

Your opponent isn't gonna move because you moved his body with that bug but you can use that to predict where his ghost might go and how you can play agaisnt it.
However, to do that, you need to spent alot of time moving your opponent's body and then move yours.

Important: You need to be playing agaisnt someone to make it works (you can't be in spectator mode).

Please fix that.