..which would make code non-namespace-aware and doesn't answer the question...The whole topic has been discussed before, actually in the thread you linked to..

Hmm, I wonder why I linked that threat, its almost like I want folks to read it and make up their own minds

I have read all the threads I can find. (Different from understanding them all perhaps) and I have not found the answer

I have been using XML examples from the RFC4918, but the two namespace cases are different in other ways too. So I will construct an example

Is it true that:

     <?xml version="1.0" encoding="utf-8" ?>
     <propfind xmlns="DAV:">
       <propname/>
     </propfind>
[download]

and

     <?xml version="1.0" encoding="utf-8" ?>
     <D:propfind xmlns:D="DAV:">
       <D:propname/>
     </D:propfind>
[download]

are the same (semantically)?

If so then the same Perl code should parse them, if not I am more confused than I thought

Worik

Update: The same Perl code and Xpath

Yes.

#! /usr/bin/perl
use warnings;
use strict;
use feature qw{ say };

use XML::LibXML;

my @xmls = (<< '__XML1__', << '__XML2__');
<?xml version="1.0" encoding="utf-8" ?>
     <propfind xmlns="DAV:">
       <propname/>
     </propfind>
__XML1__
<?xml version="1.0" encoding="utf-8" ?>
     <D:propfind xmlns:D="DAV:">
       <D:propname/>
     </D:propfind>
__XML2__

for my $xml (@xmls) {
    my $xpc = 'XML::LibXML::XPathContext'->new;
    $xpc->registerNs('x', 'DAV:');
    my $doc = 'XML::LibXML'->load_xml(string => $xml);
    say $xpc->find('count(//x:propname)', $doc);
}
[download]

لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ

Is it true that ... and ... are the same (semantically)?

They both have a root node named "propfind" in the namespace "DAV:" with a child "propname" also in the namespace "DAV:". Which shortcut was used to assign that namespace does not matter.