This is the Base App for Horde 5 applications. It handles authentication, the main menu, the portal and most configuration.

The Horde Application Framework is a flexible, modular, general-purpose web
application framework written in PHP. It provides an extensive array of
components that are targeted at the common problems and tasks involved in
developing modern web applications. It is the basis for a large number of
production-level web applications, notably the Horde Groupware suites. For
more information on Horde or the Horde Groupware suites, visit
http://www.horde.org.