Cumcord is a Discord client modification that allows you to interface with Discord's internals via plugins. Unlike other client mods, Cumcord works with all other Discord modifications out of the box and even encourages you to use them with Cumcord.
Discord's desktop client has built in modules for doing various tasks within Discord (e.g sending a message, showing a modal, etc). Cumcord allows you to access these modules via plugins.
A plugin is code written in JavaScript that uses Cumcord's built-in API to interact with and extend the Discord client. Plugins are built in such a way that they can be toggled on and off at will.
That's what these docs are here for! A basic plugin building guide can be found on this page.