Since the iPhone received Face ID, it has been impossible to put the battery % in the status bar due to the notch taking up so much space. Users had to open the iPhone's control centre to see how much battery was left.
Battery percentage was included as a feature in iOS 16, and when enabled, it displayed the percentage number directly on top of the battery indicator in the status bar. Except for the iPhone XR, iPhone 11, iPhone 12 mini, and iPhone 13 mini, it was added to all iPhones with Face ID.
Multiple users noticed on the MacRumors forums that the battery % feature in the first Beta release of iOS 16 for developers now allows all iPhones with FaceID notches display a number over the battery icon.