"Apply this patch to a clean FireRed (Squirrels) ROM."

. It is considered the industry standard for creating and playing Pokémon "ROM hacks"—fan-made modifications of the original game. Why "Squirrels"?

"Squirrels" is the name of the individual or group credited with originally dumping this specific version of the game into a digital format.

1636 - Pokemon Fire Red (U)(Squirrels) is a specific, widely used digital backup (ROM) of the original 2004 Pokémon FireRed Version 1.0 for the Game Boy Advance. It is the industry standard for Pokémon ROM hacking and is required for patching popular mods. Why This Specific Version is Used