A "repack" is not an official SEGA release. It is a third-party, compressed, and repackaged version of a pirated game. Repackers take a scene release (or another repack), apply high-efficiency compression (e.g., FreeArc, Zstandard), remove unnecessary files (other language packs, bonus videos, sometimes multiplayer components), and wrap it in a custom installer.
, always verify the source against the repacker’s official website (e.g., fitgirl-repacks.site) and run the installer in a sandbox first.