The game modding scene has a source code problem
Sometimes I like to play video games. Sometimes these games have issues, or they can be improved upon. Sometimes these issues are so severe that the game is virtually (or even literally) unplayable. Fortunately some really smart people have done a fantastic job reverse-engineering parts of these games, their file formats, or found workarounds for engine limitations. Unfortunately too often that knowledge never gets written down and just keeps rotting in someone's head.