At just 1.9GB the free download expands on the controversial ending of Mass Effect 3, featuring documents outlining the direction the game will take.
The full spoiler-ridden text is on Pastebin a plot summary is on Eurogamer.
A number of BioWare executives have publicly teased upcoming Mass Effect 3 DLC for the title.
Mike Gamble, a producer on the game, on Tuesday tweeted to his followers: "As I've said before, we do this for you! The Extended Cut was our gift to the fans. Hope you enjoyed. Also... keep your ears open over the next little while."