While you’ve probably heard of the Halo 3 Epsilon, speculated to be a near final build of the much anticipated game, nothing had previously been confirmed on what exactly it was. Well over at Xbox-scene.com they seemed to have cracked the code. Sent by an anonymous user, this email was sent to a select few who were chosen to test the latest build:

Congratulations on being selected to participate in the Halo 3 Epsilon! The Epsilon is now available for download on Marketplace!

First, unlike the Alpha, Beta or Delta, this is a very special test in that not only will you be testing nearly final Halo 3 Matchmaking, you will also be able to:
* Play Multiplayer on six maps: Snowbound, High Ground, Valhalla, Last Resort, Epitaph and our new big map, Sandtrap.
* Play Custom Games and test out full game variant editing.
* Play with the Forge and be able to cooperatively edit and save multiplayer map variants.
* Play up to 4 person co-op on a single Campaign level.
* Play and test the full Saved Film functionality, including screenshots you can view in-game for Campaign, Multiplayer and Forge.