Not really.
All of this material is made up on the fly. Well, partially. The original Arhosa was designed for a series of PbPs in 2008 or so (you were there, of course). At the end of 2009, the setting hosted a series of 4 novels (incomplete), but without much additional design work. After a long hiatus, this year a short story was published set in Arhosa (it's taken from the first of the 4 novels). And now I'm back on MMX, revamping the setting from end to end (at the suggestion of Prime, actually). So by playing in it, you're sort of choosing which parts grow. Or just straight up writing bits and pieces. Which works for me, because I'll never finish the setting on my own - at some point, I'll become more interested in my fantasy writing again and slow down development work on Arhosa. And because (like most people) my brain's ability to churn out ideas far exceeds its ability to finish them. Editing is such a pain.