XML: Anatomy of a Blizzard site

Anyone know how Blizzard builds their site? I know they use XML, but I can’t tell how it’s being built.

If you view the source of the Diablo 3 site, for example, all you see is:

 
<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="_layout/frontpage.xsl"?>
 
<page xml:lang="en-US"> 
     <frontpage/>
</page>

How is this done?