https://bugs.winehq.org/show_bug.cgi?id=43557
--- Comment #1 from Nikolay Sivov bunglehead@gmail.com --- I don't think I follow. Unicode data file has this for CP866:
--- 0xf6 0x040e #CYRILLIC CAPITAL LETTER SHORT U 0xf7 0x045e #CYRILLIC SMALL LETTER SHORT U ---
that's what we use when generating codepage tables.
If you mean that Windows is using different mappings, then make_unicode should be patched. If you mean that Windows does maps to SHORT U too, then I don't see a problem - you can't expect Wine to match Windows installation with altered nls data files.