tedster - 1:44 am on Oct 13, 2009 (gmt 0)

These new features appear under a "Google Labs" heading - along with this disclaimer:

Webmaster Tools Labs is a testing ground for experimental features that aren't quite ready for primetime. They may change, break or disappear at any time.

The source code feature, "Fetch as Googlebot", does not force a new spidering but retrieves the result of the last spidering - including the HTTP server headers as well as the HTML source.