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Thanks for the explanation. It sounds like the Readline library assumes an ASCII-only locale and sets its “convert-meta” variable to “on”. But Python assumes UTF-8 and inputs b"\xC3\xAB" to the terminal. Readline converts the input to two escape sequences: "\N{ESC}\x43" == "\N{ESC}C" (Alt + Capital C), which probably runs the “capitalize-word” command, and "\N{ESC}\x2B" == "\N{ESC}+" (Alt + Plus), which presumably generates the bell character.

I don’t understand why you say Readline is “correctly” using the C or Posix locale (ASCII), while my understanding is Python on Android always uses UTF-8 as the locale encoding. It seems there is an inconsistency with the locale or encodings being used.

Or is this just an obscure case that you choose not to support on Android, and therefore skip the test?