It's unconfirmed, but other GAF users are also saying they too read the preview of the game. Among salient facts: It will star a female assassin named Aveline, who is of mixed French/African heritage. It will be released alongside Assassin's Creed III this fall, the story will take place in New Orleans (yes!) during the same time period as Assassin's Creed III, it'll have multiplayer, and won't feature Desmond. Aveline will meet Connor from Assassin's Creed III, and her mentor will be an escaped/freed slave, which combined with the location and time period could mean that "Liberation" probably refers to the liberation of American slaves. The back-touch screen will let you pick pockets, and all of New Orleans will be explorable without any loading screens. It will also take players into Mexico. Oh, and it will feature alligators! Awesome.
That image up top is early concept art of a female assassin. Ever since meeting Shao Jun, the female assassin in the short film Assassin's Creed Embers, I've been wanting to see a female protagonist in an Assassin's Creed game. Sounds like I'll be getting my wish.
Assuming this turns out to be true, we'll almost surely be hearing more about the game next week at E3.