recordedSexOrGender includes internationalEquivalent as a separate field, but it's not clear why, and the requirements don't clarify. What value does it bring? Who would want to fill this out? Why isn't the value just a mapping? It's not obvious from the value set why it brings any additional clarity. Is it to align the statements with the other gender extensions (if so, how). Given the vague definitions, why isn't it just a matter of mapping? Is it anticipate to be consistent with the other elements.

Or does the fact that it's an ICAO gender have particular ramifications for international... civilian travel? Does it have standing for more than that, internationally? What's a reference for it?

I really didn't find a good explanation for this element.