Type of content Tags
WordArt without Alt Text or Decorative
<Sect>
  text content
Picture with Attribution
<Figure>
  Alt=alt tex
<Sect>
  text content
Group without Alt Text
tags for child objects
Hyperlink on Text
<Link>
  Link - OBJR
  text content
Hyperlink on Object
tag for object
<Link>
  Link - OBJR
  alt text
Note: the <Link> is a sibling of the tag for
the object.
The following types of content are marked as <Artifact> in the PDF Content Tree and
have no PDF/UA tags:
Header and footer
Decorative graphical objects
Gray space on the right side of the page for comments
Pictures in picture bullets
Underlines
Borders around text and quote paragraphs
Lines above footnotes/endnotes
Text in SmartArt objects
Artifacts