There are games that are only discs and do not have ROMs. These games were loaded with a copy of the BIOS with the same name.
Recently, the ROMs/BIOS were removed, and when creating the list in RetroArch, these games are not added.
They recommend creating null files to load the game. This way, they are added and work fine.
The point is, in MAME standalone, they appear in the list without the need to create null files. Is there any way to include them in the core as well?