Feels like a missed opportunity that the online version of the book isnt a demo of hypermedia in itself? Maybe a serious student of htmx could (as a learning exercise) transcribe the book from asciidoc into htmx? :-)
Besides technical merit [1] in this era of tech hypes, manias and virality it helps to engineer some gee-wow moments... 2 cents.
[1] (that htmx and friends definitely have, reminding us once again that "any fool can make something complicated but it takes a genius to make it simple")