title: How to force mime-type of file download
body: <p>When users visit our website's download page, it automatically starts the download. The page has a <code>display:hidden</code> iframe with <code>src</code> pointing to the installer file</p>
  
  <pre class="lang-html prettyprint-override"><code>&lt;iframe src="/path/to/installer.dmg"&gt;&lt;/iframe&gt;
  </code></pre>
  
  <p>This works fine so far. But my Chrome extension: "Web developer" logs this Warning message</p>
  
  <p><code>Resource interpreted as Document but transferred with MIME type application/octet-stream</code></p>
  
  <p>So, is there a way to explicitly declare installer.dmg's content-type as octet-stream, so that browsers do not get confused?</p>