Edge there means that the either HTTP header or META (don't remember which one exactly) won't specify IE version number and instead will use whatever is the lat

Edge there means that the either HTTP header or META (don't remember which one exactly) won't specify IE version number and instead will use whatever is the latest version of the browser is. In IE10 this will mean IE10's engine, in IE11 this will be IE11's. This convention is several years old and predates Edge the browser.