When searching for the "21M" or "Rev B" version, you are looking for specific metadata associated with the game's disc image.
If you fall in love with the game, support the franchise. Buy Super Robot Wars 30 on Steam, or hunt down a physical copy of SRW F for your collection. Until then, the "Rev B 21M Free" preservation copy ensures that the history of Banpresto is never lost. super robot taisen f japan rev b 21m free
Here are some general points about the game: When searching for the "21M" or "Rev B"