The current setup shows a switch that controls a ceiling fan. There is another switch (not pictured) that also controls the ceiling fan. Both switches also control power to the outlet shown in the picture. Don't love this setup, but I can deal with it. Main concern: The switch has a white wire on top (with the red knob) and black wire on bottom. Yellow wire goes from the opposite side of the switch to the hot side of the outlet. Everything appears to work, but the issue that causes my confusion is the seamingly random white wire that comes into the box through the round hole in the back (see picture towards the center of the box) and is connected to the neutral side of the outlet. The neutral that I would have expected to be connected is just left unconnected (hard to see but it is almost touching the left side of the box). What am I missing here? Is this extra wire from the ceiling fan, the other switch, or somewhere else?
Any help would be greatly appreciated.