> I dunno, you're being pedantic :)

It might be, I'm usually not, but this is all xhtml.club and this footnote are about, might as well be correct :-)

Constraint validation is still descriptive (what is allowed)

All details and summary are doing is conveying information on what's a summary and what's the complete story, and it has this hidden / shown behavior.

In any case, you will probably find something procedural / programming like in HTML, but it's not the core idea of the language, and if you are explaining what HTML is to a newbie, I feel like you should focus to the essential. Then we can discuss the corners between more experienced people.

In the end, all I'm saying is: you can just avoid issues and just say "HTML" without further qualifying it.