Horde's Registry is the glue that holds everything together.

• The Registry system keeps track of Horde's application stack, and which application is currently running.
• When you switch applications, the registry will take care of switching the gettext textdomain correctly, loading new preferences, loading the new configuration files and loading the new locale files.
• It also lets you determine configuration information about installed applications, such as where they live on the filesystem, where they are in the web tree, whether they allow guest users, and other useful information.

The Registry is one of the most complex things in Horde. Let's disect it a bit.