A mod is a container of configuration information and settings that profiles inherit from. Mods work like templates for profiles; they provide a set of base settings--such as map lists, game types, exposed files, available game images, resource usage specification (e.g., max number of players per server instance, CPU usage restriction per server instance), custom settings, configuration files (e.g., server.json, GAME.init), and command-line parameters. that profiles can inherit or overwrite. In a practical sense, it may help to think of mods as a way to maintain separate configurations for each branch of a game title (e.g., production, development, staging, etc.). You can have one or more mods associated with your game to manage different configuration needs.