Normally, this element used with for-each and apply-templates

        <pre data-sub="prettyprint:_">
        <xsl:sort
        select = string-expression
        lang = { nmtoken }
        data-type = { "text" | "number" | QName }
        order = { "ascending" | "descending" }
        case-order = { "upper-first" | "lower-first" }
        />

        </pre>