I'm willing to guess it's gonna be somewhat akin to Episode Duscae, which is to say... none of it will be in the main game.
It's possible it was formerly part of the game, but got scratched from the final product, but still being complete, and gives people a chance to try out a more finalized version of what the game will be like. It's a nice peace offering for the ten year wait.
Or maybe it is just a small little bit taken out of the game. Who knows.