A served port omits everything that matches the default
The wire shape is lean by divergence, which means a client cannot read absence as "unknown". Absence is the default, and the defaults are fixed here.
The rule
Normative: this is the rule
- A served port emits
defaultValueonly where it is not null,exposedByDefaultonly where it is false, anddisplayOrderonly where it is not 0. - A client must read the absence of those keys as no default, exposed, and order 0 respectively.
Rule identifiers are permanent and are never renumbered. Each implementation publishes its own standing against these rules; this specification does not.spec 1.0-draft · SCH-27 · changed in spec 1.0