So yesterday I was swapping out this receptacle to make room for a new instant on hot water faucet for my wife. The top outlet is switch controlled for the garbage disposal. The bottom outlet is switch controlled for the dishwasher (switch stays on 24/7). There was another hot coming off the top outlet screw (the black wire off to the right) going back into the wall. I could not figure out what this was for? Not sure what would only need power when I turn on the garbage disposal? I thought maybe it ran something for the dishwasher or a some other plumbing pump? I just wired back the way it was with the expanded receptacle and called it a day but still curious.

It's weird that it would go from the outlet, back into the wall, and then back to the outlet. Maybe re-wired a few times and was originally part of a different switch circuit? Who knows.

That box is buried back there...