OptionalalwaysOnly present when the tag is always emitted (then always true).
OptionalchainChained tags; only present when non-empty.
Default value, wire-encoded. null means OMIT: the tag has no default
and absence is its canonical state — not "unknown".
Effective maximum occurrences; null means unbounded.
Effective minimum occurrences.
Tag name including its sigil, e.g. @id, &image, #title.
OptionalvaluesEnum vocabulary — only on enum-format tags.
A tag in compact (
full: false) output.