Meanwhile... in case you've missed a few links about coding challenges on another platform below. These are fairly old but as the electronics on T6 are fairly old there seems to be some commonalities.
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VCDS (VAG-COM) codes and programmable options for Golf Mk7 - Page 23
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Help for Rain Closing | OBDeleven
Also some data of rain/light sensors installed on T6:
It seems that the six digit string right after "RLS" is build date (as "270519" above) and the rest are presumably software revision.
For the experimenting a quote from the link above:
I think it would be useful for trials if we could create artificial rain e.g. a cloth on a stick touching the sensor. Anyone to verify if it works when wipers are on with ignition/engine on?