<!--
http://www.w3.org/TR/xmldsig2ed-tests/#c14n11xmlbase-prop-5

Check that implementations of [XML-C14N1.1] properly build the xml:base 
if one intermediate level (ietf:e2) without any xml:base attribute is absent 
from the document subset.
-->
<XPath xmlns:ietf="http://www.ietf.org" >
(//. | //@* | //namespace::*)
[ancestor-or-self::ietf:e21]
</XPath>