"...support slots and are analyzed at definition time" I don't know what you meant by this. As we speak, is there a standard implementation of this "Web Templa

"...support slots and are analyzed at definition time" I don't know what you meant by this. As we speak, is there a standard implementation of this "Web Templates" thing? Can I open an editor, type "native" html, incorrectly assign to some attribute some callback with the wrong type and the editor tells me it's wrong without running the website? As for "ALL web-template based libraries beat React...", is there evidence to substantiate such claim? Surely SOME of them are not that performant. Also slots exist in most frameworks including Angular and in various 3rd packages in the React ecosystem.