MK3 media controller - what is the cable plugged to AUX-IN?

[piston_pan]

Hi folks,

Added a bluetooth module to my MK3 today, the modules goes into the aux-in socket at the back of the media controller. One strange thing is, there is already a cable in place, which is different from the youtube tutorial I found (it should be an empty socket according to the uploader). Do you guys know what is connected there?

Cheers