I don't know yet how to fix

  Error:  gui/wxpython/tplot/g.gui.tplot.html: SyntaxError: Unexpected closing tag "li". It may happen when the tag has already been closed by another tag. For more info see https://www.w3.org/TR/html5/syntax.html#closing-elements-that-have-implied-end-tags (28:3)
  Error:    26 |     because these software packages use a reference date other than
  Error:    27 |     the UNIX Epoch time (00:00:00 UTC on 1 January 1970)).
  Error:  > 28 |   </li>
  Error:       |   ^^^^^
  Error:    29 | </ul>
  Error:    30 |
  Error:    31 | <div align="center" style="margin: 10px">

I don't know yet how to fix

  Error:  gui/wxpython/tplot/g.gui.tplot.html: SyntaxError: Unexpected closing tag "li". It may happen when the tag has already been closed by another tag. For more info see https://www.w3.org/TR/html5/syntax.html#closing-elements-that-have-implied-end-tags (28:3)

  Error:    26 |     because these software packages use a reference date other than

  Error:    27 |     the UNIX Epoch time (00:00:00 UTC on 1 January 1970)).

  Error:  > 28 |   </li>

  Error:       |   ^^^^^

  Error:    29 | </ul>

  Error:    30 |

  Error:    31 | <div align="center" style="margin: 10px">

Me neither. I think I left these ones in the grass-addons, as I didn't find what it was complaining about.

I invite you to test out the linter on your side, I think it may only the first parsing error of a file, so fixing the first ones might uncover some underneath that line.

Just to make sure: do the html entities for < and > work in pre-formatted blocks? Otherwise good to go!

Looks good:

I invite you to test out the linter on your side, I think it may only the first parsing error of a file, so fixing the first ones might uncover some underneath that line.

I see errors here but not sure:
https://validator.w3.org/check?uri=https%3A%2F%2Fgrass.osgeo.org%2Fgrass-stable%2Fmanuals%2Fg.gui.tplot.html&charset=%28detect+automatically%29&doctype=Inline&group=0