Idk it finished. I did restart and stuff after that but that 14gb was gone lol idk.
Then I ran that official built in defragging thing and lost another 2gb...
I think it's pretty much like book keeping, organizes files and puts them where they belong and fixes incorrect associations so things load faster cause it doesn't have to spend time checking a bunch of locations
It's not the end that I fear with each breath, it's life that scares me to death