<!DOCTYPE html>
<html>
<head>
  <title>Download page</title>
  <meta charset="utf-8">
</head>
<body>
<!-- just use simple.mar since we have it available and it will result in a download dialog -->
<a id="download-link" href="http://example.com/browser/browser/base/content/test/appUpdate/simple.mar" data-link-type="download">
  Download
</a>
</body>
</html>
