[xsl] Document reordering after applying path expression

["Max Toro maxtoroq@xxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>]

The following stylesheet:

<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="2.0" exclude-result-prefixes="#all"
     xmlns:xsl="http://www.w3.org/1999/XSL/Transform";
     xmlns:xs="http://www.w3.org/2001/XMLSchema";>

   <xsl:output method="xml" indent="yes"/>

   <xsl:template name="main">

      <xsl:variable name="a">
         <a/>
      </xsl:variable>

      <xsl:variable name="b">
         <b/>
      </xsl:variable>

      <for-each1>
         <xsl:for-each select="reverse(($a, $b))">
            <xsl:copy-of select="."/>
         </xsl:for-each>
      </for-each1>

      <for-each2>
         <xsl:for-each select="reverse(($a, $b))/*">
            <xsl:copy-of select="."/>
         </xsl:for-each>
      </for-each2>

   </xsl:template>

</xsl:stylesheet>

Outputs:

<?xml version="1.0" encoding="UTF-8"?>
<for-each1>
   <b/>
   <a/>
</for-each1>
<for-each2>
   <a/>
   <b/>
</for-each2>

Why is the sequence reordered after applying a path expression?
Is this conformant with the standard? If yes, what section talks about it?

I'm using Saxon 9.6.0.6.

Original post: http://stackoverflow.com/questions/31126950

--
Max Toro