forever mysterious

Either someone didn't notice that whatever they did (if they even noticed that they did it) had torn off the front bit of their motor car, or they picked it up and dropped it the other side of the barrier on the footway rather than trying to take it with them, the better to restore it at some point without having to buy a new bit. At least it should be possible to identify the owner from the number plate to appropriately fine them for littering.