It looks like a technicolor vomit. ;~D
I think they do a lot of history of rock and roll type stuff, as opposed to history of all music, but the ~Cottons~ especially Bilbo Bagpipes, seemed interested in that.
There probably really is some pretty cool stuff there that Rosie & Co would seriously enjoy, from what I hear. I don't think its strictly a rock-and-roll sort of thing, but a "wholistic" thing with music across many genres.
Heck... when you're Paul Allen and you have a few extra tens of millions layin' around and you write blank checks and say "make me a music thingy" this is the sort of thing that happens.