A ROMset is a collection of ROM (Read-Only Memory) files that contain the game data for various arcade games. These files are used by MAME to emulate the games. A ROMset is essentially a database of game data that MAME uses to identify and load the correct game files.
Used for "Rollback" files that the Plus core backported.
You must obtain the mame2003-plus.dat file, often found within the libretro/mame2003-plus-libretro GitHub repository or your Recalbox/RetroPie system folders . 2. Key Differences in ROM Types
: Load the DAT into your manager and point it to your current 0.78 folder.