mb_ucfirst and mb_lcfirst

Hey internals I recently saw a comment on Reddit about the lack of a multibyte version of ucfirst and lcfirst. I was surprised to see this is indeed the case. I also checked the modes of mb_convert_case: the closest supported one is title case, but there's no mode for only handling the first letter. I have two questions (and some sub-questions): Does anyone know if there is a historical reason for this? A quick search on externals.io didn't provide something useful. Do you think this is useful? If yes, do you think this should be part of mb_convert_case or should this be a standalone function? Kind regards Niels