 is an
instruction element if its namespace URI is the standard URI for XSL elements
or if its namespace is identified in the
xsl:extension-element-prefixes attribute of a containing literal result element, or in the
extension-element-prefixes attribute of the xsl:stylesheet element.</p>

<p>If the xsl:fallback element appears in
any other context, it is ignored, together with all its child and descendant elements.</p>

<p>There are no attributes.<p>

<p>If the parent element can be instantiated 