https://bugs.winehq.org/show_bug.cgi?id=54424
--- Comment #2 from François Gouget fgouget@codeweavers.com --- The code page WM_CHAR uses is actually more likely to be based on the keyboard layout, as per Wine's get_input_codepage(). It's just that in the TestBot configurations the keyboard layout always matches the user locale.
Sent a merge request: https://gitlab.winehq.org/wine/wine/-/merge_requests/2661