Oracle SQL Plan operation RECURSIVE WITH PUMP

explain plan for
with rec(n) as (
   select 1 from dual
      union all
   select n+1 from rec where n<=1000
)
select * from rec;

select * from table(dbms_xplan.display(format=>'basic +predicate'));
-- ----------------------------------------------------------
-- | Id  | Operation                                 | Name |
-- ----------------------------------------------------------
-- |   0 | SELECT STATEMENT                          |      |
-- |   1 |  VIEW                                     |      |
-- |   2 |   UNION ALL (RECURSIVE WITH) BREADTH FIRST|      |
-- |   3 |    FAST DUAL                              |      |
-- |*  4 |    RECURSIVE WITH PUMP                    |      |
-- ----------------------------------------------------------
--  
-- Predicate Information (identified by operation id):
-- ---------------------------------------------------
--  
--    4 - filter("N"<=1000)