The Windows getpath implementation gained the ability to find and read a sys.path file to skip reading the registry.

While the name is cute, it really ought to start with a leading underscore (i.e. "_sys.path") to indicate that it is very at-your-own-risk. The docs should be updated to indicate that its behavior may be changed in later versions of Python (though it's guaranteed to only change backwards-compatibly for 3.6).

Since the file is only used with a specific installation of Python (specifically the embedded distro), this shouldn't be an issue as nobody is meant to upgrade Python without removing/replacing this file.