# File lib/mechanize/http/agent.rb, line 524
  def request_referer request, uri, referer
    return unless referer
    return if 'https' == referer.scheme.downcase and
              'https' != uri.scheme.downcase
    if referer.fragment || referer.user || referer.password
      referer = referer.dup
      referer.fragment = referer.user = referer.password = nil
    end
    request['Referer'] = referer
  end