From <a href="https://en.wikipedia.org/wiki/CDATA">Wikipedia</a>:

…as in this JavaScript example:

<script type="text/javascript">
//<![CDATA[
document.write("<");
//]]>
</script>

or this CSS example:

<style type="text/css">
/*<![CDATA[*/
body { background-image: url("marble.png?width=300&height=300") }
/*]]>*/
</style>

<foo>bar</foo>
<foo><![CDATA[bar]]></foo>

surprise ending: <![CDATA[