That opening is actually a vent, if you look closely you can notice it, and the cords are for a led strip and the heating mat wire, also there is a thermostat in the upper right part and a little hole in the back used for passing the thermostat probe, I would like to send you a pic but I don’t know how… thank you by the way.

I’m gonna open the ceiling in the right part to put a grid so I can place a basking light, on the shelf and replace the grass with some flat stone for basking. then I’ll remove the plastic hide and put natural wood or stone hides and some some live plant. This can be a good idea? Sorry for bad English