SQL> select s.grantee, r.grantee grantee_through_role
2 from dba_sys_privs s,
3 dba_role_privs r
4 where s.privilege='RESTRICTED SESSION'
5 and r.granted_role (+) = s.grantee;

GRANTEE GRANTEE_THROUGH_ROLE
------------------------------ ------------------------------
DBA COPYMGR
DBA COPYMGR_TMP
DBA MARCIO
DBA ORACLE
DBA SYS
DBA SYSTEM
AURORA$ORB$UNAUTHENTICATED

This last user I do not know.