@Patrick-Rainsberry This is pretty well what I expected except for the usage of GPIO 11 which surprises me
I have access to the circuit diagrams for the Omega1 and Expansion Dock and OLED Expansion
On these, what is marked as GPIO 11 on the pin out diagrams referenced above is used for VDD25 (i.e. 2.5Volt supply) and is used on the OLED Expansion to supply power to level shifters between the I2C signals from the Omega and the OLED display chip.
I am unable to find schematics for the Omega2 (hint to Onion devs: can we have ALL schematics for the Omega2 and related boards please :-) ) so can't tell whether this has been repurposed for the Omega2 etc. or whether the pin out diagrams for the Omega2 etc in the Omega2 docs referenced above are wrong in this respect