luci/modules/luci-base/luasrc/view/header.htm

<%#
 Copyright 2008 Steven Barth <steven@midlink.org>
 Copyright 2008 Jo-Philipp Wich <jow@openwrt.org>
 Licensed to the public under the Apache License 2.0.
-%>

<%
	if not luci.dispatcher.context.template_header_sent then
		include("themes/" .. theme .. "/header")
		luci.dispatcher.context.template_header_sent = true
	end
%>