moby/docs/theme/mkdocs/beta_warning.html

{% if aws_bucket != "docs.docker.com" %}
<div class="box alert-red-body alert-red-block">
	This is the
  <span>{% if docker_version != docker_version|replace("-dev", "bingo") %}{{ docker_branch }} development branch{% else %}beta{% endif %}</span>
	documentation for Docker version {{ docker_version }}.
	Please go to <a class="alert-red-link" href="http://docs.docker.com">http://docs.docker.com</a> for the current Docker release documentation.
</div>
{% endif %}