You're seeing only three contributors at https://github.com/bigguysoftware/htmxxx/graphs/contributors...? I have no explanation for that, it doesn't match what I'm seeing.
GitHub's contributor graph is based on authorship of Git commits, and doesn't track whether a given GitHub account ever actually interacted with a given GitHub repo. This Git repo is a fork of the htmx Git repo (though it's not marked as such on GitHub), so all contributors to htmx as of the fork date are also contributors here.