On August 29, 2026, a massive 13 terabyte archive was released online containing many builds of every single game ever uploaded to the pre-2013 Steam content server system (internally called steam2). While this mainly consisted of typical release versions of games that already are or had once been available - it also included a huge amount of pre-release builds which had been uploaded to Steam but were never normally accessible, due to either being replaced before release or uploaded to alternate development AppIDs.
Although the archive contains metadata for every build ever uploaded to Steam before 2013, most of the builds prior to 2007 or so seem to be missing their actual data.