Sprint Silly Question

I have a silly question here. On the bodywork of my Sprint, there is a oblong hole above where the passenger (left) footpeg is -- one side only. Does anybody know what this hole is for? I was going on a trip about a month ago and needed to figure out how to tie down a sleeping bag to the seat when I noticed it. I almost used it to hook a bungee into it and then noticed there was not one on the other side. I went to the footpeg frame instead.