Mattermost plugins are isolated pieces of code written in Go and/or React. They’re separate from the main repositories and are used to extend the functionality of the Mattermost server and webapp.
The plugin Help Wanted tickets are located in each plugin’s respective GitHub repository. In order to browse all of the open tickets, see the plugin Help Wanted tickets page with links to specific plugin repositories, as well as queries for Help Wanted tickets in all repositories. The All Plugins Up for Grabs link is useful to browse all repositories at once.