Hmmm...,
green-black or black-green...
I should know that.
Well, the black wire with green marker line is for sure the right side turn signal (and black-whiteis the left side). That's not it in this case.
However, the attached loop on the wire looks factory to me.
A green wire with a black marker line instead is for the left side parking light. Could illuminate your side marker lens perhaps.
But that also does not make sense since that wire should come from the (left) headlight unit.
So...? I don't know.
Maybe something additional for your shut-off/idle relais. US-version 280 ? (if I see this correctly).
I don't know .... I'll leave this to the experts.
Achim