"Moreover, am I wrong to think that if you use hx-boost to swap in fragments, then the URL that gets updated/saved in history wouldn't actually load the same page if you loaded it from a bookmark? That wouldn't happen with non-boosted anchor links."

It's a common pattern with Django and template partials that you check if the request is an AJAX request, in which case you just load a partial template to swap into the existing DOM. Or if it's not an AJAX request, your server-side logic loads the full template.

A simple example would be a to-do list at http://example.com/todo/. Clicking on a task item would swap it into the DOM without a full page load, and then you'd update the URL and browser history to http://example.com/todo/my-task/. Then if you open that URL in a new session, your server side logic would render your page with the "my-task" already selected.