HTML is generally updated by injecting new code into your page via hot reloading, and then having your code update the relevant parts of the page, normally a div including the entirety of the page content.

There is no such thing as hot reloading an entire HTML document. That would just be plain old reloading.

Sound like you a looking for a tool to trigger a js/document.reload on file changes. I'm sure there are plenty of those, but that's not what figwheel is for.

That clarifies. But since Figwheel promises to reload on CSS change, I thought HTML is possible too.

It hot loads CSS into the existing document. The way browsers work, reloading the entire HTML document is best done with an actual reload.