It's pretty much used to help make a complete backup of your PC. As it contains possibly all your stored information.
I might be wrong, but if so, feel free to correct me.
Well, it is in my recovery drive, which is apart of my c:/ drive, the main drive. But honestly, I don't need a backup since I am about to get a better hard drive anyway... I might just wait until the new hard drive comes in before deleting it, incase i fuck up this hard drive doing it lol
It is used by windows/mac or any drive recovery program to recover important data if lost.
do not delete it.
If your hard drive corrupts and you've deleted it, good luck getting your shit back.