[XML-SIG] Parsing namespace attributes (e.g., xml.dom.ext.GetAllNs)

[Rich Salz]

According to my reading of the namespace spec, "xmlns" is not a
namespace identifier, but is instead just lexically significant.  Yet
xml.dom (cf Document.py and ext/__init__.py) treats it as if it were a
namespace, and uses it to find namespace nodes.  Is that just an
implementation technique?

Where is the "xmlns" defined in a W3 recommendation?  For example, in
dom/__init__.py:
	XMLNS_NAMESPACE = "http://www.w3.org/2000/xmlns/"
I can't find that value in W3C docs -- what am I missing?

I'm asking for a couple of reasons.  First, I might be missing something
on the specs.  Second, I need to add this to xml/ns.py if it's really
there, and third, it seems that if I'm write, then there's a
(minor/obscure) bug.
	<tns:foo xmlns:tns="uri:zolera.com" xmlns="uri.zolera.com"
	xmlns:foo="http://www.w3.org/2000/xmlns/">
		<bar foo:tns="uri:example.com">
			<tns:testit>value</tns:testit>
		</bar>
	</tns:foo>

What namespace is "testit" really in?  I believe uri:zolera.com
	/r$