There are dozens of HTTP server variables that can be included in a page's expanded XML. Including all potential variables would make the XML unnecessarily large, so the CMS lets you select the server variables to include in site pages at runtime.

Most of the default server variables provide access to client-side information about page requests. You can also configure custom variables to be included on request. Please note that including custom variables via System Options does not create new variables. It simply includes the value of custom variables if they already exist.

There are three kinds of variables that can be configured.