<div>
  This field works in conjunction with the proxy server field to specify the
  username used to authenticate with the proxy.

  <p>
    If this proxy requires Microsofts
    <a href="https://en.wikipedia.org/wiki/NTLM">NTLM</a>
    authentication scheme then the domain name can be encoded within the
    username by prefixing the domain name followed by a back-slash '\' before
    the username, e.g "ACME\John Doo".
  </p>
</div>
