India, Sept. 9 -- A game leak does not need stolen source code or an unfinished build. Sometimes a few achievement names and images can reveal enough to spoil months of carefully planned announcements. That appears to be the issue surrounding Exophase, a third-party achievement tracking service that has reportedly indexed Steam achievement pages tied to several unreleased games. The listings include Persona 6, Kingdom Hearts 4, Ace Combat 8, Judas, Deus Ex Remastered, and other projects.

The data has not been independently verified, and there is no evidence in the supplied reporting that Steam accounts, Valve systems, or game files were compromised. What may have leaked is metadata, which can still expose story details, platform plans, a...