What makes a game moddable? For instance GTA5 and RDR2 have several trainers that allow significant control over game play, why? Other games have no such trainers but have many other mods. Is it because of the game engine or have people just decided not to make trainers for some games. Sorry if this is a vague question that misunderstands basic modding knowledge, but I really don't know enough to figure it out. Thanks.