I would love to know the answer to that question also. I have the same switch setup and can't figure it out either. My other side outdoor light is on the same switch as the door side. The double switch on mine is indoor lights and the orange outside lights. The single one is a mystery. Could it be for awning led lights and if so is it prewired out to the awning?
2013 Jayco Whitehawk 30DSRE
2017 F250 6.7 Platinum 4x4