<p>For info, I see the same "problem" in SeaMonkey 2.39 on Windows, not other browsers.  I'd always assumed that it was the browser "trying to be clever" and populating a previously-used username.</p>

<p style="font-size:small;-webkit-text-size-adjust:none;color:#666;">—<br>Reply to this email directly or <a href="https://github.com/openstreetmap/openstreetmap-website/issues/1169#issuecomment-190727894">view it on GitHub</a>.<img alt="" height="1" src="https://github.com/notifications/beacon/ABWnLQqza9uDruF0c7If2HdS1FNBft6zks5ppEIGgaJpZM4HmXzW.gif" width="1" /></p>
<div itemscope itemtype="http://schema.org/EmailMessage">
<div itemprop="action" itemscope itemtype="http://schema.org/ViewAction">
  <link itemprop="url" href="https://github.com/openstreetmap/openstreetmap-website/issues/1169#issuecomment-190727894"></link>
  <meta itemprop="name" content="View Issue"></meta>
</div>
<meta itemprop="description" content="View this Issue on GitHub"></meta>
</div>