LuckPerms is a permissions plugin for Minecraft (and now Torch SE) servers. It allows server admins to control what features players can use by creating groups and assigning permissions.
For more information, see the wiki article on Why LuckPerms?
Right now its an entire implementation of luckperms common apis, so config and commands are (mostly) the same as original minecraft version.
There is full api support for plugins. For details refer to Plugin Api - Getting started