System Tables Views Oracle PLSQL

SQL>
SQL> select role, password_required
  2  from dba_roles
  3  where rownum < 50
  4  order by role
  5  /
ROLE                           PASSWORD
------------------------------ --------
AQ_ADMINISTRATOR_ROLE          NO
AQ_USER_ROLE                   NO
AUTHENTICATEDUSER              NO
CONNECT                        NO
CTXAPP                         NO
DBA                            NO
DELETE_CATALOG_ROLE            NO
EXECUTE_CATALOG_ROLE           NO
EXP_FULL_DATABASE              NO
GATHER_SYSTEM_STATISTICS       NO
HS_ADMIN_ROLE                  NO
IMP_FULL_DATABASE              NO
LOGSTDBY_ADMINISTRATOR         NO
OEM_ADVISOR                    NO
OEM_MONITOR                    NO
PLUSTRACE                      NO
RECOVERY_CATALOG_OWNER         NO
RESOURCE                       NO
SCHEDULER_ADMIN                NO
SELECT_CATALOG_ROLE            NO
XDBADMIN                       NO
XDBWEBSERVICES                 NO
22 rows selected.
SQL> --