https://posix.rhansen.org/p/gettext_draft Line 960
"Do we need to say this isn't used for message strings, only for parsing the .po file?" The .po file format has a mechanism for specifying the codeset of the PO file. See line 1009. Therefore LC_CTYPE is *not used* for the interpretation of the input .po file, only for producing diagnostics (in combination with the LC_MESSAGES category).
