First, a reality check: Pokémon Pigment Ruby is a real Pokémon game released by Nintendo or Game Freak. There is no cartridge, no official eShop download, and no mobile version.
Projects labeled as "completed" and "free" typically follow a specific distribution model to avoid legal issues: download 18 pokemon pigment ruby completed free
You must provide your own legally obtained ROM of the base game (Pokémon Ruby). First, a reality check: Pokémon Pigment Ruby is