You got me, Nemo. :-)
Ryan, who is the right person to ask?
Everyone who is interested in having structured metadata for Commons always stumble upon
that mysterious page (at leats, the few who are insterested in OAI-MPH), and I think it would be good to understand more of it once for good.
At least, we could know if could be useful or not.
As you perfectly know, the issue of not having a reliable/proper system for "metadata communication" (call is as you like) is a perennial issue, and I bet many of us
would like to have it on developers priorities (at least, for Commons) :-)

Thanks for the information!

Aubrey