Will be interesting to see if they find anything about the TF2 animated show they planned with Adult Swim, but eventually canned. That and elements from the comics I always suspected were meant to turn up in said show.
I think he means whatever became of Episode 3. I would love to see a leak of that that the mod community could go ham on. There have been a ton of fan mods that attempt to recreate what Ep 3 might have been but if they actually had some maps and stuff to work off of, it would be a game changer.
Zhain uploaded a quick summary showing some interesting bits and bobs from the leak. Fk'n called it, 0:27 for 'female soldier'. Looks a lot like Heavy's sister from the comics.