These are highly accurate, byte-for-byte disc images (typically .bin / .cue format) verified against multiple physical copies to ensure preservation-quality data.
Because the hardware is so complex, the quality of the disc image matters immensely. Emulators like Mednafen (Beetle), Yabause, or the retroarch cores require
What amount of storage is required to have the full Sega Saturn library?
It provides a "clean" list of the ~1,100 unique games released for the system without the clutter of regional variants. for a specific Saturn ODE or emulator?