Magic Reset Button

[Woodworker]

Does anyone know what this is? This happens several times a day, every day.

We have the 3811MS. Right inside the door, below all the switches, is a fuse box with all the reset fuses. Inside the fuse box is a recessed reset button with a green light. The light flashes and when I stick my finger in the recess and push the reset button it stays on and stops flashing.
Sometimes the rear AC has stopped and the reset fixes it. Sometimes it's the gas/electric HWH. It has never affected by the television or residential refrigerator.
I've attached a photo. The flashing light is on the right about three inches from the top.

Any ideas what this is and what it's for?

we call it the magic reset button!