Since ROMs exist in a legal grey area, you won't find them on official app stores. To find the set, use these reliable search terms on reputable archive sites: "MAME 2003 Reference Set"
: Use this if you only need specific game files rather than the entire multi-gigabyte set. mame 078 rom set download link
Once you have found and downloaded your MAME 0.78 set: Since ROMs exist in a legal grey area,
If you're looking for more information on MAME 0.78 or ROM sets, here are some additional resources: here are some additional resources: