From Fedora Project Wiki

GNOME Software in Fedora 21 enables a feature that allows addons / plugins that are packaged in Fedora to be visible on the Application page for the application that is being extended. For example, here is Audacious, showing it's available plugins that a user can add right from the software Application:


Getting your plugin to show

If you are the package maintainer for a plugin for Fedora for an application, this is the process to follow to get that plugin to show in the application.

First, create a name-of-the-plugin.metainfo.xml file for your plugin, for example:

<?xml version="1.0" encoding="UTF-8"?>
<component type="addon">

  <!--name of the plugin package-->

  <!---name of the main application desktop file-->
  <extends><!- e.g. "eclipse.desktop"--></extends>

  <!--Nice name of the plugin-->

  <!--one-sentence description of the plugin-->
  <summary>Provides vim-like editing in Eclipse</summary>

  <!--URL for the plugin-->
  <url type="homepage"></url>

  <!--license for this file (not the plugin license)-->

This needs to be installed to /usr/share/appdata and should be packaged so the .metainfo.xml file is packaged with the subpackage/package that installs the required functionality. Any metainfo files shipped in the same sub-package as the main application .desktop will be ignored automatically by the metadata generator.