Oracle SQL Plan operation: CONNECT BY WITHOUT FILTERING

explain plan for
select level as n from dual connect by level <= 100;

select * from dbms_xplan.display(format=>'basic');
--
-- ---------------------------------------------
-- | Id  | Operation                    | Name |
-- ---------------------------------------------
-- |   0 | SELECT STATEMENT             |      |
-- |   1 |  CONNECT BY WITHOUT FILTERING|      |
-- |   2 |   FAST DUAL                  |      |
-- ---------------------------------------------