It's nothing special. You can compare it to the auto discovery of RSS feeds on certain sites. The same is done for search functionality, provided you have a compatible browser, which are currently Firefox 2 and Internet Explorer 7. In those browsers you can search the forum directly through the build in search box in the browser toolbar.
I don't have a demo, because I only have 3.6 running on a test forum behind a password. You can set up one easily on your own 3.6 board by importing the XML and visiting your forum with IE7 or FF2.
Again, this is nothing shocking, but rather something for the people who want to support every possible standard out there. I made it just to see if it could be done (quickly), and it could. This morning, I didn't even know I was going to build it