Door opening problem half-solved

My 'new' secondhand A3 cabriolet had a passenger door problem: it will lock with the fob but not unlock so the passenger can open it from outside. Otherwise everything fine. I examined door frame wiring and it's all good so I bought a new lock having watched many Youtube videos where I learn it's a pretty common VAG problem. However, before changing the lock I discovered by chance that unclipping the yellow wiring connector in the lower left corner of the (RHD car) passenger door appears to solve the problem (see image). As far as I can tell without any repercussions. Door locks and unlocks properly now and the window works. I can't imagine this location is anything to do with the wing mirror or speaker. So what is it for? It has two thin wires, white and brown and there is continuity of both to the door pillar plug.  Basically, is it safe to drive the car without plugging this back in?