A massive leak of Steam data totaling more than 12TB has surfaced, containing files published between 2003 and 2013. The archive includes beta builds and finished games from Valve franchises such as Half-Life, Left 4 Dead, and Portal, alongside titles from major series like Call of Duty, Fallout, and Civilization, plus indie developer projects. A GitHub catalog has compiled most of the leaked titles, which also feature early versions of Portal 2, CS:GO, the unreleased F-Stop, and references to the canceled Half-Life 2: Episode 3.

Community researchers are still analyzing the data, uncovering details about F-Stop — a planned Portal prequel involving a camera that manipulates real-world objects — and other unused assets. According to X user Gabe Follower, the leak originated from a publicly accessible endpoint that Valve used before switching storage systems in 2013. Valve has not commented on the leak, and Engadget has reached out for a response.