I imagine the FRCS will have DMing information, towns, maps, adventure ideas, hooks, possibly even some full adventures and/or a starting town (DMG style).
My best guess is that they are trying very hard to have books with DM information, and books with player information. and keep most of that separate.
FRCS seems like it's going to be. "here's what you need to run in FR, get to it lest thay own your punk ass."