What Is It???

SInce no one had an immediate answer that should have been obvious to me, I explored a little more this morning. I decided the gray area was a cap that might pop off. I gently pried with a small screwdriver and it came off. Big anchor bolt underneath that appears to go into the van body structure. I think it was a spot for a shoulder seatbelt strap if wanted. There was a removable 3rd bucket just forward from the anchor that had a lap belt. I decided I need an extra kitchen cabinet more than a 3rd seat so removed the seat and base plate.

Thanks for the guesses, I was sure it was something obvious to everyone but me.