Electrical Connection in bed???

Just bought a Tundra about a month ago and was loading the bed with some things and noticed a there was a plug back there. Anyone seen something like this before or know what it is? It has a fuse connected to it but I’m not sure what this could be for?

 

looks like someone added the wiring for an additional connection, maybe to a topper or a bed plug setup. Its nice its already there so you can add something pretty easy. I would just follow the wire and make sure things are connected properly.

 

Topper 3rd brake light? Pull out tail light and see if it was tapped.

 

Thanks everyone, I'll do some more digging to see where the wiring leads. Might be an excuse to buy a topper!