showdown/test/functional/makehtml/cases/standard/html-comments.html

<!-- a comment -->
<!-- a comment with *bogus* __markdown__ inside -->
<p>words <!-- a comment --> words</p>
<!-- comment -->
<p>words</p>
   <!-- comment -->
<pre><code>&lt;!-- comment --&gt;
</code></pre>
<p>&lt;!----------------------------------------------------------------------------------------------------------------------------------------------------</p>
<!-------------------------------------------------------------------->