MD is a nearly ideal format. I keep my personal notes and time management stuff in Obsidian using markdown. Write my blog in Markdown. AsciiDoc is nice, too, for certain use cases.

The next step is for Cloudflare to introduce a proprietary markdown tags, then release a library to parse their new crap, then update their systems so it serves degraded 'legacy' markdown but include a paid API to get access to the 'new' markdown, then add features to the library that can only be accessed by API customers, etcetc

I see a commercial entity embrace something and start looking for the extend and extinguish part.

Yes, and the way this reader functionality works is using structured tags in the HTML code. A very small effort that leads to a magnitude in accessibility that some just do not give an F about.

The kicker here is that these tags also impact SEO heavily, so not having them not only makes it harder for many people to use or read some sites, but it also makes them score lower on search engines.