title: complete list of mime-type <-> file extension mapping
body: <p>I can't find a complete list of mime-type mappings on the internet.
  I would like to have a list that refers a file extension to every existing mime type.</p>
  
  <p>The list of all mime-types can be found here: <br>
  <a href="http://www.iana.org/assignments/media-types" rel="noreferrer">http://www.iana.org/assignments/media-types</a></p>
  
  <p>but that resource doesn't include the file extension mapping.<br> </p>
  
  <p>I googled a while and couldn't find a mapping list with all mime-types. Only lists with most common ones. In all lists I found for example this entry is missing:</p>
  
  <pre><code>application/vnd.openxmlformats-officedocument.wordprocessingml.document   -&gt;  .docx
  </code></pre>
  
  <p>Does someone know a resource where to find a complete mapping?</p>