ThatOrThis

Normally Fabric Loader reads only the default mods folder. ThatOrThis reads additional user-selectable directories as well, and uses a set of rules to decide which of those mods to load. Rules are written in a JSON5 file, and the mod checks dependencies and conflicts at runtime before launch. The mod is open source under the MIT License, with its source code and issue tracker publicly available.

Installation goes into the mods folder alongside ModMenu and Fabric API. Settings are changed on a screen opened through ModMenu, and option names come with tooltips that support formatting codes and translation keys. New settings take effect only after the game is relaunched. Without any changes the mod runs under a default, limited rule set.

The mod is built mainly for modpack developers, who can use it as a workaround for mod sets that cannot run together. It targets Minecraft 1.16.5 – 1.17.1 on Fabric Loader, with files for 1.16.5, 1.17 and 1.17.1, and the latest file is 0.2.6+1.17 for 1.17.1. Either side can run it, and neither needs it, so it can be installed on a client, a server or both.