The System module is integral to the site, and provides basic but extensible functionality for use by other modules and themes. Some integral elements of Drupal are contained in and managed by the System module, including caching, enabling and disabling modules and themes, preparing and displaying the administrative page, and configuring fundamental site settings. A number of key system maintenance operations are also part of the System module. For more information, see the online handbook entry for <a href="@system">System module</a>.