I found this out today.

Hall effect rotary switches are popular, it means the electronics can be sealed while still being about to detect an input. Common on a lot of dive lights as well.

I wondered why the F my light kept turning on when i plugged in my USB-C magnetic charging adapter.

:/

Hold your magnet on the other side and it turns on the color side light, same with the bottom of the switch turning on the white side light.

Magnet 💍….= auto on

Can confirm…. it works with a regular magnet, and turns on whatever mode the dial is set too.