Confluence supports markdown natively. Even its MCP uses markdown.

I don’t know exactly what the other issue is referring to.

Confluence used to be built on top of pretty standard plain wiki markup that could be edited without being forced into a bad visual editor, even easy to edit in an external text editor to not have to spend so much time in the web UI at all. I remember having an Emacs mode for it installed.

Looking this up now, Wikipedia says the wiki markup was abandoned already in 2011. Not that I think Confluence was ever a great wiki, but at least having pages that were backed by some resonable plaintext markup was much better than not having that.