Comment by bloak
> the world's most popular OS
Wikipedia claims that Android "has the largest installed base of any operating system in the world", if you're going to measure popularity that way.
(Of course it's hard to know how to define an OS. Is Android a kind of Linux? Are the various things called "Windows" or "MacOS" to be regarded as different versions of the same OS just because marketing people decided to use the same name? If not, how much similarity in code or design is required?)
Can you even consider Android a singular OS? I personally don't in the same way I don't consider Fedora and Ubuntu the same OS, and there's far more differences between something like HyperOS and AOSP/PixelUI as there is between Ubuntu and Fedora.
Android is an app platform.