Understanding wiring of duo micro-switch

Hi, as part of a remote controlled lawn-mower project, I am tinkering with a battery powered lawn-mower.
I want to turn it on/off remotely. I was planning to control the switch via a MOSFET or optocoupler - easy.

However, when disassembling the switch-box, I found a duo - microswitch:
It has 3 cables connected. In off-state the voltage is as shown:
The control circuit is potted, so I cannot get more information of the wiring.

This setup sparked my interest. Why is there a third cable? What setup would you expect in the control unit?

I could emulate the duo-switch with a 2 channel relay board, but I would want to understand the setup first.

Many thanks to all replies helping to solve the mystery.

Microswitches are all current limited. Yours looks to be a dual switch with the contacts paralleled to carry the extra current.
What ever you design must be able to handle the current that the switch carried. Best to measure that current.