Unlike standard MAME, which updates its "full set" frequently to include more accurate (but more hardware-intensive) data, is a "libretro" core based on MAME 0.78. It has been backported with thousands of improvements from newer versions of MAME, such as:
: Unlike other "historic" cores that stay frozen in time, this set is actively updated with support for new games and features like Save States Libretro Forums How to Use the Romset Mame 2003 Plus Roms Archive
These archives are typically offered as Non-Merged (each game file contains everything it needs to run) or Split (common files like "BIOS" are kept separate to save space). Legal and Safety Note Unlike standard MAME, which updates its "full set"