About the auto scheduled job GATHER_STATS_JOB

Hi,
When I run the following query in my system , I found 2 rows in return :

SELECT a.job_name, a.enabled,c.window_name,c.repeat_interval
FROM
   dba_scheduler_jobs                       a,
   dba_scheduler_wingroup_members b,
   dba_scheduler_windows                 c
WHERE job_name='GATHER_STATS_JOB'
And       a.schedule_name=b.window_group_name
And       b.window_name=c.window_name;

JOB_NAME                    ENABLED    WINDOW_NAME                   REPEAT_INTERVAL
GATHER_STATS_JOB    TRUE           WEEKEND_WINDOW            freq=daily;byday=SAT;byhour=0;byminute=0;bysecond=0
GATHER_STATS_JOB    TRUE           WEEKNIGHT_WINDOW         freq=daily;byday=MON,TUE,WED,THU,FRI;byhour=22;byminute=0; bysecond=0

My questions are :