From: David Carlisle <davidc@xxxxxxxxx>

> How can you tell if an XSLT implementation implements Namespace nodes (in
> the XDM sense), if it does not support the namespace axis?

Like this, for example:

<xsl:stylesheet version="2.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

  <xsl:template name="main">
    <xsl:variable name="x" as="item()*">
      <xsl:namespace name="a" select="'data:,a'"/>
      <xsl:namespace name="b" select="'data:,b'"/>
      <x/>
      <xsl:attribute name="c" select="'c'"/>
    </xsl:variable>
    <xsl:value-of select="count($x)"/>
  </xsl:template>
</xsl:stylesheet>

This should produce the result 4, and it's hard to see how it can do so
unless the fist two items in $x are namespace nodes.

But I contest your assertion that it should produce the answer 4.
Either 2 or 4 look acceptable answers to me.