> Perhaps generalize this as splitext(basename(sys.executable))[0] in
> order to support names other than "python" and "pythonw". It would have
> to handle quoting enough to ignore an initial double quote when parsing
> the executable name out of an args string, or _winapi could wrap the
> shell's CommandLineToArgvW function to handle this.

This is where we've hit the point of complexity that it would have to be added as a new API. And since it's now opt-in, we may as well document that shutil.which() is the recommended way to resolve a filename against PATH (and make that work properly... ISTR it has some inconsistencies with the OS).