Original: Pokémon entered its third generation with the 2003 release of Pokémon Ruby and Sapphire for Game Boy Advance and continued with the Game Boy Advance remakes of Pokémon Red and Blue, Pokémon FireRed and LeafGreen, and an enhanced version of Pokémon Ruby and Sapphire titled Pokémon Emerald.
Simplified: They are for the Game Boy Advance. Pokémon FireRed and LeafGreen are new versions of Red, Blue and Yellow for the Game Boy Advance. It had a sequel for Game Boy Advance called Pokémon Pinball Ruby & Sapphire.