Python Windows release and encoding

[Absalom K.]

Hi, I am working on Linux; a friend of mine sends to me python files from
his Windows release. He uses the editor coming with the release; he runs
his code from the editor by using a menu (or some F5 key I think).

He doesn't declare any encoding in his source file; when I want to try
his code, I have an error since he obviously uses non-ascii characters.
As far as I can see, he uses utf8 without knowing it. I add the UTF8
declaration, run the code, and everything is fine.

Then I tell him to add the utf-8 declaration; but now he has an error
when running his file from the Windows editor.

Finally, he told me he could run the file by declaring the latin-1
encoding.

But I want to understand exactly:
  a) what is the encoding used by the editor coming in the Windows release?
  b) why doesn't he need to declare the encoding (I need it on Linux for
     the very same files)?

Best regards, ak.