Okay since I was curious, I went out and took a few pics in the dark. Hopefully they will be clear enough to see. It appears that the piece is a bumper for the compartment door. Maybe to help if the furnace exhaust and water heater get hot, so the door doesn't melt? It looks like it is the same bumper used behind the man door. Let me know if this helps. Yeah, wish there was a clip for the door. If you are not perfectly level when dumping or filling, its a pain to keep the door open.