Posted by Kobolitewhat are the romfs files.
game editor =/= game. a standalone level editor for a game is only the editor, this is not Mario Maker. the game isn't inclued.
so you have to get it yourself. depending what game you want and what console it's for, you can get it from google or dump it yourself if you actually own the game.
ever heard of ROMs? it's basically the game you have on your cartridge, but extracted into a ROM-image.
in case of 3DS games, it's named a romfs. romfs files are the files are extracted from a unpacked romfs.