I found it in my glove box after I bought the car, just never bothered looking into it until now. I translated the German (?) on it to "safety battery terminal". Any ideas?

 

battery terminal cover

 

Weird. I wonder why it would be in my glovebox and not on the car. This is what my battery looks like now. I figured out how it would fit but that little screw above and to the right of the little yellow plug in the bottom right is preventing it from snapping into place. I've had the car for a while now with no issues so I might just leave it off haha