That would easily be solved with an API call that says "Hey, i'm helloworld.py". It wouldn't solve the sandboxing stuff, but TBH i do not see that working for desktop applications (in that the sandboxing wont be mandatory for backwards compatibility - the main reason people keep using Windows - and most desktop applications wont bother restricting themselves).
The whole effort reminds me of W3C doubling down on XHTML despite everyone else ignoring it (and it isn't like XHTML wasn't nice on paper, but real world has other concerns beyond doing some things the theoretically "right way").
> That would easily be solved with an API call that says "Hey, i'm helloworld.py".
That's what this is! "Hey, I'm helloworld.py and I'm a Python application". Just an API call isn't going to work because every application is potentially hostile.
Windows 10X is sandboxing Win32 application through a virtualization layer.
The whole effort reminds me of W3C doubling down on XHTML despite everyone else ignoring it (and it isn't like XHTML wasn't nice on paper, but real world has other concerns beyond doing some things the theoretically "right way").