Why they can't figure out how to update the browser independently of the OS is beyond comprehension. IE and Edge are the only non-evergreen browsers which is probably they are the most problematic to target. I develop primarily in Firefox, but I never have bugs pop up in Chromium or WebKit browsers, only IE and Edge.
I thought because `iexplore.exe` is a thin wrapper around `mshtml.dll`. I'm not sure how thin, but most of the functionality is in that and maybe other DLLs.