[ttybird]

To respond to your question: no. Not sure why you linked me the PDF 2 specification. PDF/UA is from 2012, and the ability to tag PDF files for accessibility is a thing since 2001 (with PDF 1.4).

Various tools and packages that attempted to generate accessible pdfs from LaTeX have existed for aeons, all of they had a common characteristic: they sucked. I am convinced that by this point everyone who cares about accessibility has moved to other formats (like HTML).

"HTML does not"

<aside> is "first class".