Published schemas carry the flag only where the default is hidden

What it means

What a node type publishes states only its own decision, and only where that decision diverges from the default. A processor's own schema for the same port is never consulted at publication time and never survives into what ships — even where the node type's stored value agrees with the processor, or contradicts it outright, the published schema is built from the stored value alone.

Example

{ "connectable": true, "exposed_by_default": false }

{ "x-exposed-by-default": false }

Where the node type's own stored value is anything else — unset, or an explicit true even against a processor schema that itself declares x-exposed-by-default: false for that port — the published schema carries no such key at all. A processor's own value for the key never reaches what publishes; only the node type's stored word does.