If you are looking for this file, it is likely because you want to play one of the following high-profile community projects: Pokémon Radical Red
This specific file name refers to a of the Pokémon FireRed ROM (version 1.0) for the Game Boy Advance. 1636 Pokemon Fire Red - U-- Squirrels
This appears to be a of Pokémon FireRed for Game Boy Advance, possibly from a ROM set labeled with "Squirrels" (a common scene release group or pack naming convention from the early 2000s). If you are looking for this file, it
Here is a deep dive into what this file is, why the "Squirrels" release became the industry standard, and how it continues to shape the Pokémon community today. Anatomy of the Filename 1636 Pokemon Fire Red - U-- Squirrels