From the announcement:
Welcome to the public Avatar beta test! Included in this file is the avatar upgrade for each master in the game. Have a look, try them out, and give us feedback in the playtest forum. We will update these cards based on your feedback, and a new version of the file will be posted every Tuesday between 4 and 6pm PST. The rules for avatar upgrades are on pages 56-57 of the big rulebook, so please read them carefully.
We will also be playtesting some new generic upgrades for each faction, but those will not be available until next week. This playtest will continue until late April.
Enjoy, and thank you for helping shape this great game!