When you save a game in an RPG Maker XP Pokémon fan game, the engine takes the current "scene" and serializes it into a file—usually ending in .rxdata (or .rvdata / .rvdata2 in later engines, though XP is strictly .rxdata ). This file contains everything: your party, your PC storage, your location, variables tracking your progress, and switches determining which Gym Badges you own.