The simplest form of dependency between plugins is that one plugin can declare itself to be a sub-plugin of another plugin by specifying that plugin in the parent-plugin field. Sub-plugins are displayed in the control panel plugin chooser within the expandable area of their parent plugin. For example, the official plugin library includes the CodeMirror Plugin and also more than a dozen sub-plugins that extend the CodeMirror plugin with optional functionality. Note that sub-plugins cannot themselves have further sub-plugins.

Plugins can also use their dependents field to list the titles of any other plugins that should also be installed. Note that the list is not resolved recursively: dependents of dependents will not be installed.

When installing a plugin from the plugin library, both the parent-plugin and dependents fields are used to determine any additional plugins to be installed.

Note that the dependents field is also used by the ThemeMechanism and the LanguageMechanism to switch in dependent theme/language plugins.