This same logic can literally be applied to anyone working on anything. Engineers, carpenters, pilots, literally anyone. I bet there are many people who know e

This same logic can literally be applied to anyone working on anything. Engineers, carpenters, pilots, literally anyone. I bet there are many people who know everything about "XMLHttpRequest", but know nothing about congestion control. Or how a network stack comes together... You do realize "XMLHttpRequest" wasn't even a thing until several years ago, and it's safe to assume further down the road it may well be phased out (in favor of better/more secure APIs). Instead of asking about "XMLHttpRequest", wouldn't it be better to talk about the general need for "websites" to communicate with a backend on demand, at runtime, after everything has been loaded and rendered? Or, put "XMLHttpRequest" on the table, and talk about how one would implement such an API within the context of a browser?