Why is there HTML comment markup for internal CSS stylesheet

You may have come across this:

<style type="text/css">
<!--
h1 {
  font-weight:bold;
}
-->
</style>

The HTML comments are used for older browsers that can’t interpret CSS, so they are instead commented out. For most modern browsers, the HTML comment is no longer needed for this internal CSS stylesheets. But it is good to know why they exist if you ever stumble across them.