<span class="special">[[=</span><span class="identifier">col</span><span class="special">=]]</span></code>,
        matches any character or collating element whose primary sort key is the
        same as that for collating element <span class="emphasis"><em>col</em></span>, as with collating
        elements the name <span class="emphasis"><em>col</em></span> may be a <a class="link" href="collating_names.html" title="Collating Names">symbolic
        name</a>. A primary sort key is one that ignores case, 