w.w3.org/1999/XSL/Transform">
    <xsl:output method="xml" encoding="utf-8" indent="yes" />
    <xsl:strip-space elements="*"/>

    <xsl:template match="@*|node()">
        <xsl:copy>
            <xsl:copy-of select="document('non_existent.xml')/*"/>
        </xsl:copy>
    </xsl:template>
</xsl:stylesheet>z