title: svg tag with xmlns is required?
body: <pre><code>&lt;svg aria-hidden="true" role="img" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 576 512"&gt;
  </code></pre>
  
  <p>There is xmlns= <a href="http://www.w3.org/2000/svg" rel="nofollow noreferrer">http://www.w3.org/2000/svg</a> is this required/nesesery? If yes, why?</p>