If you want to include HTML sandboxes, we have iframes. If you want it served from the server, it's just text. Putting text A inside text B is a solved problem.
> Putting text A inside text B is a solved problem.
Yes, but in regards to HTML it hasn't been solved in a standard way, it's been solved in hundreds, if not thousands of non standard ways. The point of the article is that having one standard way wlcould reduce a lot of complexity from the ecosystem, as ES6 imports did.
