I'm sorry, I haven't been following this thread as closely as I
should to contribute, so slap me upside the head if I'm off target or
repeating already trodden ground, but ...
> The representation of y30000-070 as year-month-day depends ...
Can you explain why on earth representing the year 30,000 in a
standard for 21st century bibliographies should be a use-case?
Even if homo sapiens are not extinct, we will very likely have
developed a somewhat different calendaring system by then, and
certainly different computer systems. I have a really wild
imagination, but I just can't come up with why this is useful to do
in this context.
Yes, some astronomers may want to talk about dates that far in the
future in books they write, but they don't use dates with respect to
a calendar when they do, (and if they did, let them come up with
their own standard! :-)
The bibliographic data about a book that says "30,000 years in the
future" (or "the year 32011", or even goes so far as to mention a
specific date in the year 30,000) still refers to the 21st century,
not the year 30,000.