What this will do is allow you to view the user agent string and referer information of an anonymous user provided there is any. If there is referer information an icon will be displayed that provides a link to the location the anonymous user came from. The referer information is also displayed in the "alt" display of the icon by mousing over it. User agent information is intersting as you can see if it's a google bot browsing your site or whatnot. (not always though)
This code modification is also in use here at ThreadsDev. (if there are no anonymous users online you won't see anything)
