Toberton

Hi, I hope somebody can help. I'm not much of a boffin with the car but I need help identifying a piece off the front. I noticed this square off the front of the bumper area was removed exposing some kind of pipe, if you can see the picture. What on earth is this bit for? Why is it removable? Why the hell would somebody take the time to remove it? And finally should I be concerned?? It was parked in the work multi storey car park when I spotted it as being removed. Am reasonably certain it had been attached in the morning. Car park is notorious for not having adequate cctv so not going to hold my breath on finding anything out.