Optional ReadonlydescReadonlynameOptional ReadonlyopaqueValues may have no JSON form (a class instance, a buffer); never checked. Its shape is {}.
Optional ReadonlyoptionalInputs only: a caller may leave it out (it then takes its shape's default, or stays out).
ReadonlyshapeJSON Schema, read by the vocabulary programs.md lists. {} is any JSON value.
Optional ReadonlytypeThe host language's name for the type, for people.
A field of an interface (programs.md, "The interface").