If you are looking at this from a technical or "internet mystery" perspective, these files often pop up in three types of deep-dives:
: By late 2022, the game had transitioned from a single-rival demo (Osana Najimi) to the "1980s Mode," which featured a full cast of 10 rivals. This version was part of the refinement period for that mode. Yandere.Simulator.v15.09.2022.rar
: Data-miners often write about these builds to track "hidden" assets—models or scripts for future rivals (like Amai or Kizana) that the developer occasionally leaves in the game files by accident. If you are looking at this from a