As @portastar suggested
address bar should only display the zoom level if it doesn't match the website's setting, or if that doesn't exist, the global setting.
this removes some clutter for those who have a default zoom that isn't 100%.
in preferences - set slashdot to use 120%
visit slashdot at default 100% zoom and it shows up in address bar
set zoom to 120% and the address bar value disappears since it matches the preferences