title: HTML Comments without DOCTYPE
body: <p>I'm running into a config issue with a Angular/AMP setup that I'm trying to debug. I have a hunch on what the problem could be, but I'm having trouble verifying if some compilers might misunderstand a HTML comments without <code>&lt;!DOCTYPE html&gt;</code> present (which is an issue in itself).</p>
  
  <p>To provide a simple overview of the page I'm working with, the site renders something like the below within the DOM on the none AMP page (note the lack of <code>&lt;!DOCTYPE html&gt;</code>). </p>
  
  <pre><code>&lt;html&gt;
  &lt;head&gt;
    &lt;!----&gt;
      &lt;link rel="amphtml" href="https://www.foo.com/amp/document.html"&gt;
    &lt;!----&gt;
  
  &lt;/head&gt;
    &lt;body&gt;
      &lt;p&gt;Foo site&lt;/p&gt;
    &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>The Angular template will check if the site is a valid AMP page and will return the AMP link if so, and will leave behind <code>&lt;!----&gt;</code>. </p>
  
  <p>I realize that a valid HTML comment is something like <code>&lt;!-- foo --&gt;</code>, however could a compiler possibly interpret something like <code>&lt;!----&gt;&lt;link rel="amphtml" ... &gt;&lt;!----&gt;</code> as a comment when <code>&lt;!DOCTYPE html&gt;</code> isn't present? Specifically, could <a href="https://developers.google.com/search/docs/guides/rendering" rel="nofollow noreferrer">Chrome 41</a> see this as a comment? </p>
  
  <p>Viewing the AMP link within Chrome 63 everything looks valid, but I'd like to rule out this one hypothesis before continuing to dig in the problem. </p>
  
  <p>Many thanks in advance and apologies for the silly question :) </p>