Htmx posits that current browsers aren't "truly" hypermedia since only anchor tags and forms can initiate GET/POST requests. It is more of a tech demo showing what client with ANY tag being able to do requests would look like.

That's why whether it is library/framework is besides the point. The author posits that these features should be in the spec, and tries as closely as possible to show what something might look like if we had it in the spec