A leaked 12-terabyte archive containing builds of every game uploaded to Steam between 2003 and 2013 has surfaced online, and researchers combing through it have already uncovered assets from Valve's long-cancelled Half-Life 2: Episode 3, alongside content cut from Portal 2. The find is significant for game preservation and fan communities, offering an unprecedented look at abandoned and early-development versions of major titles from both Valve and third-party studios, though the sheer scale of the leak means much of its contents remain unexamined.

Among the discoveries so far are a build of F-Stop, an unreleased Portal-universe game built around a camera mechanic, and early or alternate versions of Call of Duty and Resident Evil instalments, plus builds of Mirror's Edge, Batman: Arkham Asylum and Dragon Age: Origins. The most striking finds relate to Portal 2, including deleted dialogue that recontextualises the Companion Cube, alternative intro and GLaDOS sequences, and a version of the "Weaponizer" tool originally intended for the scrapped Half-Life 2: Episode 3.