@jxn: Yes, that’s what I meant – encodings are the same. So a file created with de_DE.UTF-8 is on a binary level the same as one created with en_GB.UTF-8, so actually it shouldn’t matter if a program created them with one locale and another program or instance of the same reads them with the other locale 😉 (shouldn’t matter with any Unicode, but as mentioned, there are a lot of versions of the UTF-8 standards since it was expanded and changed a few times to include more languages with new characters)
locales change lots of things, like ordering, currencies and script(how characters ar coded).
So in this case, the only thing interesting is the character coding, which is the same in both locales you tested, namely UTF-8.
And for your (and our) purpose, any change in Unicode doesn’t matter. And there are not lots of Unicode. It’s lots of locales that uses same script coding, UTF-8.
Anyway, locale C (or de_DE.ISO-8859-1) and de_DE.UTF-8 (or en_GB.UTF-8) is a difference. locale C use ASCII (which mostly is equal to ISO-8859-1 in locale de_DE.ISO-8859-1) and the others use UTF-8. That could make a difference in any character outside of ASCII (remember, only 7 bits, no åäöÅÄÖ in ASCII, but in ISO-8859-1). Lots of balls in the air right now 😉