Why do you want to change this?

The current behavior is consistent with the platform name (Darwin). I’ve filed an issue in the past to change the platform name to “macosx”, but there were good arguments to not change the behavior at the time. The existence of iOS might change that though. 

W.r.t. failing when the Plist is not present: that is unlikely to happen because this is a system file that is hard to remove and is AFAIK documented to exist. 

If the platform version info gets changed, the platform name should change as well. 

Ps. Sorry about the lack of references, I’m away from my computer.