The two tags look to be spring clips of some sort, so it must be part of the bodywork? If there isn't a comparable-sized hole in the pressed steel for it to clip into, it might be another candidate to hang on that nail on the shed wall!
I've just bought a "new" bike, and with it there is a box of "unknowns" which may or may not have anything to do with the bike. Always a challenge!
Leon