My understanding is that UTF-8 is the world's charset and that reasonable Hungarians would use that (e.g. I sure don't use us-ascii or iso-latin-1 if I can at all help it. I mean my "better half" reads 中文 so I don't have to and having it all in UTF-8 makes it easy) The other mystery is how the data sci's found it.

IIRC there was some widely used image with many derivatives that redefined locale (the one in Docker Library used POSIX since forever).