"Google Search Appliance virtual edition is a developer platform designed for the enterprise development community to build and test applications that use the Google Search Appliance."

This is just a free download for developers who want to write applications for the Search Appliance. It's one-step up from a free SDK.

There's also some good info on what you can do with it at http://google-code-updates.blogspot.com/2008/11/announcing-g...