Switch to nothing

I have three switches at my front door. One is for the hall light, one is for the porch light, one goes to a junction box in the basement but it is not hooked up to anything. What was it meant for? If there stairs were anywhere near there I would have thought it was meant to turn on a light before going down, but that is not it. I put a meter on the end and it's definitelyhot when the switch is on.