I integrated this snippet in my personal "post-install" script, among with some other adjustments for OS-specific settings, database parameters and the fix for the mixed up datafiles (sysaux and undo).
cd $ORACLE_HOME/rdbms/admin sqlplus / as sysdba @catnsnmp @catsnmp shutdown immediate; startup; exit
You'll see a short description for most predefined jobs in the comments section. If you want to know more, I recommend "RTFM" or your preferred search engine on the job name.
SELECT job_name, comments FROM dba_scheduler_jobs ORDER BY job_name;