In practice, that means the company that runs your phone’s operating system—Apple or Google, for the overwhelming majority of Americans—will decide how push notifications function in your life.

Push notifications […] aren’t sent directly from the app provider to users’ smartphones. Instead, they pass through a kind of digital post office run by the phone’s operating system provider.

iOS notification changes. At the time, Apple said that the new bottom-up design for iOS 16 notifications was meant to reduce the clutter on your Lock Screen.