Okay, forget XML for a moment, let's just look at marc 'binary'.
First, for Anglophone-centric MARC21.
The LC docs don't actually say quite what I thought about leader byte
09, used to advertise encoding:
a - UCS/Unicode
Character coding in the record makes use of characters from the
Universal Coded Character Set (UCS) (ISO 10646), or Unicode™, an
That doesn't say UTF-8. It says UCS or "Unicode". What does that
actually mean? Does it mean UTF-8, or does it mean UTF-16 (closer to
what used to be called "UCS" I think?). Whatever it actually means, do
people violate it in the wild?
Now we get to non-Anglophone centric marc. I think all of which is
ISO_2709? A standard which of course is not open access, so I can't get
it to see what it says.
But leader 09 being used for encoding -- is that Marc21 specific, or is
it true of any ISO-2709? Marc8 and "unicode" being the only valid
encodings can't be true of any ISO-2709, right?
Is there a generic ISO-2709 way to deal with this, or not so much?