format 2.1: .ocn_range is one of the properties

Format 2.1 adds .ocn_range, the first and last ocn a container holds,
emitted after .last_descendant: a poem, which now carries ocn 0 and
comes before its verses, is cited as the range of them. Both readers
now know it as the forty-third property, so --validate accepts a 2.1
file and --report-unknown does not list it. The validator's message
counts the list rather than naming a number.

Every document-language of the markup document samples written by
spine at 2.1 validates; neither reader uses the property, which
within a major version is conforming.

(assisted by Claude-Code)

0 files changed, 0 insertions, 0 deletions