<RDF:Description about="urn:mozilla:extension:{E48C5243-3A54-4e0d-9652-59D90E4B3AB9}">
   <em:version>1.1</em:version>
   <em:updateLink>http://downloads.mozdev.org/firstfield/firstfield-1.1.xpi</em:updateLink>
</RDF:Description>