Oh, now I know what you mean! This game was originally made in RPGMaker... I want to say VX? I don't remember which one, it was many years ago. When you compile the game into an .exe for people to be able to play the game, RPGMaker also adds its runtime package of contents to whatever custom assets that might be present. What you are seeing are the RPGMaker runtime package assets - the base graphics and sounds and such that come with RPGMaker.