//*[ local-name() != 'propfind'
     and contains(local-name(), 'prop')
     and namespace-uri() = 'DAV:' ]  
##</code><code>##

$ cat  dav-rfc4918-dingaling.xml
<?xml version="1.0" encoding="utf-8"?>
<D:propfind xmlns:D="DAV:">
  <D:prop xmlns:R="http://ns.example.com/boxschema/">
    <R:bigbox/>
    <R:author/>
    <R:DingALing/>
    <R:Random/>
  </D:prop>
</D:propfind>

$
$ cat  dav-rfc4918-allprop.xml
<?xml version="1.0" encoding="utf-8" ?>
<D:propfind xmlns:D="DAV:">
  <D:allprop/>
</D:propfind>
$
$ cat  dav-rfc4918-propname.xml
<?xml version="1.0" encoding="utf-8" ?>
<propfind xmlns="DAV:">
  <propname/>
</propfind>
$
$
$ xmllint.exe --xpath " //*[ local-name() != 'propfind' and contains(local-name(), 'prop
') and namespace-uri() = 'DAV:' ]  "     dav-rfc4918-dingaling.xml
<D:prop xmlns:R="http://ns.example.com/boxschema/">
    <R:bigbox/>
    <R:author/>
    <R:DingALing/>
    <R:Random/>
  </D:prop>
$
$ xmllint.exe --xpath " //*[ local-name() != 'propfind' and contains(local-name(), 'prop
') and namespace-uri() = 'DAV:' ]  "     dav-rfc4918-allprop.xml
<D:allprop/>
$
$ xmllint.exe --xpath " //*[ local-name() != 'propfind' and contains(local-name(), 'prop
') and namespace-uri() = 'DAV:' ]  "     dav-rfc4918-propname.xml
<propname/>
$