I'm unsure if I've submitted this under the proper components. But it would be nice of the build % complete would show in the browser tab if I have it open, so that I can continue working in other tabs and know when it's done. Usually this would be done by appending/prepending the percentage to the <title> of the HTML.
Perhaps even the favicon could change from blue to red to green?
It's certainly an unimportant feature, but it would be very nice.