Mark, the /U and /A switches to CMD only affect (as the help messages say) the output of internal CMD commands. So they would only affect interoperability between internal command output piped to a Python program. The biggest issue in this bug, however, is the output of Python programs not being properly displayed by the console window (often thought of or described as the CMD shell window).

While my biggest concerns have been with output, I suppose input can be an issue also, and running the output of echo, or other internal commands, into Python could be an issue as well. I have pasted a variety of data into Python programs beyond ASCII, but I'm not sure I've gone beyond ANSI or beyond Unicode BMP. Obviously, once output is working properly, input should also be tested and fixed, although I think output is more critical.

With the impetus of your question... I just took some text supplied in another context that has a bunch of characters from different repertoires, including non-BMP, and tried to paste it into the console window.  Here is the text:


こんにちは世界 - fine on Linux, all boxes on Windows (all boxes in Chrome on Linux too)
مرحبا، العالم! - fine on Linux and Windows
안녕하세요, 세계! - fine on Linux, just boxes and punctuation on Windows
(likewise in Chrome)
Привет, мир! - fine on Linux and Windows
Αυτή είναι μια δοκιμή - fine on both, but Google Translate has a
problem with this! It returned "Hello, world!" as the Greek for
"Hello, world!"... so I tried again with "This is a test".
𝓗𝓮𝓵𝓵𝓸, 𝔀𝓸𝓻𝓵𝓭! - not actually a language, but this is astral
In the console window, which I have configured using the Consolas font, the glyphs for the non-ASCII characters in the first two and last lines were boxes... likely Consolas doesn't support those characters. I had written a Python equivalent of "echo", including some workarounds originally posted in this issue, and got exactly the same output as input, with no errors produced. So it is a bit difficult to test characters outside the repertoire of whatever font is configured for the console window.  Perhaps someone that has Chinese or Korean fonts configured for their console window could report on further testing of the above or similar strings.