> Thanks to the fixed nature of both LOSE and ISO 8601, the following
> pipeline will extract just the build date:
>
> fantastic-scheme -V | grep '^(build-date' | cut -d' ' -f2 | cut -c2-11
>
> The first "cut" gives us the second space-delimited field, the
> second gives us the 2nd through 11th character, which is precisely
> yyyy-mm-dd.

While this will work fine for the fixed-length date properties, all
other properties in the spec have variable-length values, so these would
be a special case.

Anyway, it's probably not as useful as I thought to get just the date
from build-date and image-date, so I'll change them to use a single
combined date/time string as you suggest.

Is it OK to demand the use of "T" as the separator character between
date and time? ISO 8601 also accepts a space.

What about time zones? For parsing it's useful to rely on UTC, but for
display to humans a local time is easier. Do you know how widespread the
library support is for parsing local times if the UTC offset is stated
at the end of the timestamp?