Rum is used throughout, though mostly via middleware[1], so you (almost) never see any calls to `rum.core/render-static-markup`. But all of the hiccup-style data structures (`[:div "foo"]`, etc) do get rendered by Rum.

htmx doesn't render anything on the backend; rather it gives the frontend more ways to interact with the backend. e.g. say you make an inline form--htmx gives you the ability to display/submit that form without refreshing the entire page, but all the html that's sent to the frontend is still getting rendered first by Rum.

[1] See https://github.com/jacobobryant/biff/blob/6353c406adef034448... and https://github.com/jacobobryant/biff/blob/6353c406adef034448...