Multiple versions of a game (clones, regions) are packed into one zip file.
Search for "MAME 2003-Plus Reference Set Full Non-Merged." This is the most common home for these sets. mame 2003plus reference full nonmerged romsets link
Arcade emulators are not like console emulators. You cannot simply use any MAME ROM with MAME 2003-Plus. The emulator expects the files inside the zip to have specific checksums and filenames. Multiple versions of a game (clones, regions) are
MAME 2003-Plus is a high-performance arcade emulator designed specifically for libretro frontends like RetroArch and RetroPie. It is widely considered the gold standard for mid-range hardware like the Raspberry Pi 3 or 4, balancing speed with an expanded feature set. Multiple versions of a game (clones