I have tried a few API, and the closest I get is the
ProcessInfo.processInfo.operatingSystemVersionString
which gives a string like Version 15.2 (Build 19E258)
Note that I am not asking about device.systemVersion, which is 15.2
I am wondering if there's an API that returns 19E258 without me having to parse the string (because apple may change the format of the string in the future)