visibility property
Visibility is "public" (the default when absent) or "private". Publishing publicly is ungated — that is the point of a community. Going PRIVATE is the paid feature, so an unfunded org asking for it is refused rather than silently downgraded (see resolve).
Please note: This property should have been non-nullable! Since the specification file does not include a default value (using the "default:" property), however, the generated source code must fall back to having a nullable type. Consider adding a "default:" property in the specification file to hide this note.
Implementation
String? visibility;