what is this in the wall for?

I was touring apartments today and found this is the wall in the bathroom. as you can see there is a small hole near the bottom in the back. my boyfriend says it looks like the back of a toilet paper holder but a roll would clearly fall out lol anybody know what specifically goes here?

I was touring apartments today and found this is the wall in the bathroom. as you can see there is a small hole near the bottom in the back. my boyfriend says it looks like the back of a toilet paper holder but a roll would clearly fall out lol anybody know what specifically goes here?