Description of json_value_return_type

{ ( VARCHAR2 [ ( size [BYTE | CHAR] ) ] [ TRUNCATE ] )
  | CLOB
  | NUMBER [ ( precision [, scale] ) ] 
  | ( ALLOW | DISALLOW ) [ BOOLEAN ] TO NUMBER [CONVERSION]  )
  | DATE [ { TRUNCATE | PRESERVE } TIME ]
  | TIMESTAMP [ WITH TIME ZONE ]
  | BOOLEAN
  | SDO_GEOMETRY
  | JSON_value_return_object_instance
}