(Reported by Zsolt):
Studying the differences between the 2.1.7 and 2.2 CVS HEAD versions of the taglib.tld, I noticed 2.2 doesn't have the <uri>webwork</uri> declaration. This is legal, but it means in the JSP files one would need to declare the use of the taglib like this, pointing to the webwork jar file:

<%@ taglib uri="/WEB-INF/lib/webwork-2.2-beta-4.jar" prefix="ww" %>

This can be of course overridden in the web.xml, but I suppose people would tend to forget that.

By adding the uri declaration the above can change to this:

<%@ taglib uri="webwork" prefix="ww" %> which looks more clean to me, and it is not prone to breakage if the webwowk jar file name changes.

I also noticed the jsp files in the shopping-cart app declare the uri as "/webwork".

References:
http://forums.opensymphony.com/thread.jspa?threadID=10605&messageID=22322#22322