intended semantics of hgroup?

Last Tuesday allyproject.com published an article recommending fleshing out hgroup with additional semantics. This is the gist (direct quote):

Until browsers add the information themselves do:

  *   Add role="group" and aria-roledescription="Heading group" as attributes to the hgroup element.
  *   Add the subtitles in a paragraph (not a heading) <p aria-roledescription="subtitle">.
Then all information about the structure and connection of the headings group is given for assistive technology in the accessibility tree.
<hgroup role="group" aria-roledescription="Heading group">
  <h1>My heading</h1>
  <p aria-roledescription="subtitle">My subtitle or tagline</p>
</hgroup>

https://www.a11yproject.com/posts/how-to-accessible-heading-structure/#hgroup

.. . .

What are the intended semantics of hgroup?

Adding aria-roledescription to the subtitle seems unnecessarily verbose. Without a "subtitle" or similar role description the paragraph's understood as text that contributes to the heading. Do we really need to say "subtitle", "alternative title" or "tagline"?

Those won't work in all cases ...

<hgroup role="group" aria-roledescription="heading group">
  <p aria-roledescription="author">Tom Clancy's</p>
  <h1>Rainbow Six</h1>
</hgroup>

<hgroup role="group" aria-roledescription="heading group">
   <p aria-roledescription="????">Based on the Marvel comic book: </p>
   <h1>Ant-Man</h1>
</hgroup>

Seems like noise ...

<hgroup role="group" aria-roledescription="heading group">
   <h1>ALIEN</h1>
   <p aria-roledescription="tag line">In space no one can hear you scream..</p>
</hgroup>

All the best,

Jeff

Jeff Orchard, MI

Accessibility Coach, Information Technology Accessibility Unit
Employment and Social Development Canada / Government of Canada
IT Accessibility Office
jeffery.orchard@hrsdc-rhdcc.gc.ca<mailto:jeffery.orchard@hrsdc-rhdcc.gc.ca> / Cell: (416) 450-7498

Coach en accessibilité, Direction générale de l'Innovation, de l'information et de la technologie (DGIIT)
Emploi et Développement social Canada / Gouvernement du Canada
Bureau de l'accessibilité des TI
jeffery.orchard@hrsdc-rhdcc.gc.ca<mailto:jeffery.orchard@hrsdc-rhdcc.gc.ca> / Téléphone: (416) 450-7498