(fyi to those of us holdouts..) On the older ones with real keys it does the same thing: alt+volume => opens sound prefs alt+brightness => display prefs alt

(fyi to those of us holdouts..) On the older ones with real keys it does the same thing: alt+volume => opens sound prefs alt+brightness => display prefs alt+mission control => .. alt+keyboard backlight => keyboard also, unrelated but occasionally useful.. alt+shift allows you to adjust volume/brightness in fractional increments.