Question about wall-Hack

Hi,
I am wondering what Wall-Hack Really does.

Is it like you can shoot true the walls?
Or you just can see to them?

What does it really do?

Ty vm,
Guppie11

makes walls dissipate, so they become transparent, but you get lost easily if its a building map such as montana, or havana, its best for BG. so u can see ur enemies coming etc.