From a cursory look, it appears they wrote all the new functionality in C++ (and ObjC for UI on the Mac). That's a lot of work. Why they didn't do the bulk of i

From a cursory look, it appears they wrote all the new functionality in C++ (and ObjC for UI on the Mac). That's a lot of work. Why they didn't do the bulk of it in JS/HTML/CSS is anybody's guess.