While MAME itself is perfectly legal open-source software, the commercial distribution of ROMs containing copyrighted code (game data) is generally illegal in most jurisdictions.
An "index of MAME ROMs" typically refers to a comprehensive directory or "ROM set" containing digital copies of arcade game software. These files are used with (Multiple Arcade Machine Emulator), a project dedicated to the preservation of vintage software by documenting and emulating its original hardware. What are MAME ROMs? index of mame roms
Many games require separate system files (like the Neo-Geo BIOS) to run. Without these in your "roms" folder, the index remains unplayable. MAME Documentation 3. CHDs: The Giant Files If you see an index with files ending in , these are Compressed Hunks of Data While MAME itself is perfectly legal open-source software,