This test was double-checked with the HuM demo project, Premium Pack 5.2 and the template V5 Coolmax Webhelp.
(After seeing it first in my own project.)
a) Result in HTML code for the header section:
<td id="topicheadercell">
<div id="topicheaderwrapper">
<p id="ptopic_breadcrumbs" class="topic_breadcrumbs">Navigation: <a href="hm_quickstart_explorer.html">Using the Project Explorer</a></p>
<h1 class="topictitle" title="Navigating in the Project Explorer">Navigating in the Project Explorer<h1>
</div>
</td>
The h1 tag is not correctly closed in the end of "Navigating in the Project Explorer<h1>".
b) In the rendering in the browser this leads to a closed h1 tag (good) plus an extra line of
<h1> </h1> (not so good), as visible in the dev tools.
<td id="topicheadercell">
<div id="topicheaderwrapper">
<p id="ptopic_breadcrumbs" class="topic_breadcrumbs">Navigation: <a href="hm_quickstart_explorer.html">Using the Project Explorer</a></p>
<h1 class="topictitle" title="Navigating in the Project Explorer">Navigating in the Project Explorer</h1>
<h1> </h1>
</div>
</td>
c) This then leads to an error in accessibility checkers for "empty headline" / "missing H1" or alike.
Counterchecks:
if the </h1> is fixed in the HTML code, the empty <h1> </h1> does not appear in the browser.
The theme V5 Modern FlexKeyboard does not have that problem. There, </h1> is closed correctly.
I assume the not-closed <h1> results from the file "hm_webhelp.js", but I couldn't fix it myself. A solution would be great
All the best, Birgit