Enormous 12TB Steam leak includes abandoned Half-Life 2: Episode 3 assets

A massive 12TB Steam leak reportedly contains builds of games uploaded to Steam from 2003 to 2013. Early findings include canceled Half-Life 2: Episode 3 assets, cut Portal 2 content, the Portal-universe prototype F-Stop, and early builds of major third-party games.

The leak could become a major source for game preservation, modding, and historical research, but it also raises legal and security concerns for Valve and affected publishers. Its scope highlights how much unreleased or transitional development material remains hidden inside platform archives.