title: Is there a difference between the UTC and Etc/UTC time zones?
body: <p>In the PHP documentation, <a href="http://php.net/manual/en/timezones.others.php">list of supported time zones</a>, <code>UTC</code> is listed twice:</p>
  
  <ul>
  <li><code>UTC</code></li>
  <li><code>Etc/UTC</code></li>
  </ul>
  
  <p>Is there any conceptual difference between those two, or are they just synonyms?</p>