s.tld in jboss-seam.ui.jar/MANIFEST.MF/ is not valid as it contains two errors.

There are two attribute entries in s.tld that are invalid according to the schema defined in
http://java.sun.com/xml/ns/javaee/web-jsptaglibrary_2_1.xsd .

These attribute entries can easily be found as both contain the words "Alias for" in their description element.

It's my guess that these two entries are generated out of the alias entries in
\ui\src\main\config\component\selectItems.xml