Special files This information is valid for Horde 4 only. See Doc/Dev/SpecialFilesH3 for Horde 3 or Doc/Dev/SpecialFiles for Horde 5 and later. horde/lib/core.php: This file sets some required PHP configuration settings sets autoloading paths for Horde libraries registers error handlers There are several files with a special meaning that can be found in every Horde application: index.php: This script is loaded if a user enters an application. Usually this script doesn't have any functionality but simple loads the default view of the application, sometimes depending on the user's preferences. lib/Api.php: This files defines and implements all methods that an application is exposing through the Registry to the other Horde applications and the Horde RPC servers. lib/Application.php: This file defines information need to initialize the application and to interact with the Horde framework. It also defines the version number of the application. lib/Test.php: This file defines any application specific tests to run when using the Horde test script. templates/common-header.inc: This is the common page header template for all scripts of the application. All applications use the same page footer template horde/templates/common-footer.inc. themes/default/screen.css: This is a CSS file that defines all application specific style sheet rules.