[throw1234567891]

UTF-8 is a character encoding and therefore it cannot serve as a locale. There is no UTF-8 language, punctuation, date and number formats…

[numpad0]

I mean, UTF-8 string handling is language (of the given bitstream, not necessarily the system) dependent, e.g. Turkish lowercase I, Chinese Hanzi vs Japanese Kanji at same codepoints, etc etc...