Factory? Hole in the floor board some one identify for me please

[Revelation]

Noticed right after I got my truck on the transmission hump right where it slopes up to go over the bell housing there is a hole in the floorboard metal and the black liner. It's clean cut, looks factory not like some hack cut it with a torch or saw. Is it factory for a truck with an option I do not have? If so what's it for and should there be a plug for it? I'm worried about carbon monoxide coming in the cab through the hole. Any ideas?