hidden property
Hidden is PLATFORM MODERATION, and it is a different axis from visibility: it pulls a public project out of the catalogue without editing the publisher's own choice, so un-hiding restores exactly what they asked for. A project is listed only when it is public AND not hidden. Always present, never omitted, for the same reason as visibility.
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
bool? hidden;