bath module

While testing a fix for my show floor drain, I found that the closet flange wasn't completely sealed to the floor of the fiberglass shower shell. Water was running under the toilet, past the flange, down the hole onto the top of the tank and falling on the ground. So after I removed the toilet...

hi all, does anyone know what this is for? I think it may have been some sort of optional thing that was never completed but have no idea what for. I showed it to Jim Bounds and he also had one at his place with the same thing but said it was the only other one he had seen. at the top is a...