Thanks. Did some searching around and yes it's likely related to MULF2/Combox etc. I wonder if factory just puts in the harness and hardware added later depending on options ordered.
Found a post
here on upgrading to Combox which I think confirms the wires are for the TCU. Btw, the post is probably the most detailed DIY post in the history of posts..
I'm more interested to see if I can utilize that MOST connection to wire up an OEM Top Hifi Amp. Similar to what was successfully done
here.