MOD is the abbreviation of English word modification (meaning modification), and Chinese transliteration is "module", also known as game module, which is a modification or enhancement program of the game.

The game module is to modify props, weapons, characters, enemies, things, patterns, story lines and so on. In computer games, or adding new props and things, this is more common in sandbox games such as Grand Theft Auto and the ancient scrolls.

Simply put, players can make and modify equipment, figures, maps, tasks, etc. Do it yourself in the game, such as adding the equipment and weapons from Loki the legend of heroes to the ancient scrolls.