Apple has just released a beta version of the brand new Safari 4 browser. Safari 4 beta is available for both Mac OSX and Windows.
On Mac, Safari 4 identifies itself with the following user agent. The Intel Mac OS X 10_5_6 token represents the os version the client is running, in this case Leopard.
Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_5_6; en-us) AppleWebKit/528.16 (KHTML, like Gecko) Version/4.0 Safari/528.16
The following one identifies Safari 4 on Windows. The Windows NT 5.1 token represents the version of Microsoft Windows os the client is running, in this case Windows XP.
Mozilla/5.0 (Windows; U; Windows NT 5.1; it-IT) AppleWebKit/528.16 (KHTML, like Gecko) Version/4.0 Safari/528.16
Safari version can be extracted from the Version/4.0 token, regardless the operating system behind the browser. Even in Safari 4 the browser doesn't forsake the habit of injecting the cryptic Apple web kit version in the final user agent. You can see it identified by the token AppleWebKit/528.16.