Better to assume UTF8 and fail with a clear message/warning. Sure you can offer to guess to help the end user if it fails, but as other people have pointed out,

Better to assume UTF8 and fail with a clear message/warning. Sure you can offer to guess to help the end user if it fails, but as other people have pointed out, it’s been standard for a long time now. Even python caved and accepted it as the default: https://peps.python.org/pep-0686/ https://peps.python.org/pep-0686/