Type of content Tags
Objects that appear in Slide Master View
no tags (except 
hyperlinks)
Title Placeholder on first slide in presentation or section or
slide with Title or Section Header layout <H1>
Title Placeholder on all other slides
<H2>
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:
Decorative objects
Header and footer
Objects that appear in Slide Master View
Table borders
Text formatting marks including underline, strikethrough, highlight, and shadow
Text in SmartArt objects
Artifacts
Bookmarks