Explanation

REVOKE ..FROM
If the current container is the root: / Specify CONTAINER = CURRENT to revoke a locally granted system privilege, object privilege, or role from a common user or common role. The privilege or role is revoked from the user or role only in the root. This clause does not revoke privileges granted with CONTAINER = ALL.
/ Specify CONTAINER = ALL to revoke a commonly granted system privilege, object privilege on a common object, or role from a common user or common role. The privilege or role is revoked from the user or role across the entire CDB. This clause can revoke only a privilege or role granted with CONTAINER = ALL from the specified common user or common role. This clause does not revoke privileges granted locally with CONTAINER = CURRENT. However, any locally granted privileges that depend on the commonly granted privilege being revoked are also revoked.
If you omit this clause, then CONTAINER = CURRENT is the default.
Reference: Oracle Database SQL Language Reference 12c, Revoke

Explanation/Reference:
References: https://docs.oracle.com/cd/B28359_01/server.111/b28310/schema003.htm

Explanation/Reference: https://docs.oracle.com/cd/B19306_01/server.102/b14231/archredo.htm