The init.ora parameter - REMOVE_INACTIVE_STANDBY_TDE_MASTER_KEY is not recognized

Hi ,

Oracle documentation recommends using parameter `REMOVE_INACTIVE_STANDBY_TDE_MASTER_KEY` in init.ora to remove the unused encryption keys.

https://docs.oracle.com/en/database/oracle/oracle-database/19/asoag/managing-keystores-encryption-keys-in-united-mode.ht…

However ,when I attempt to set the parameter in the database (version 19.3), I  get the error below.  Is this is a bug?

SQL> alter system set REMOVE_INACTIVE_STANDBY_TDE_MASTER_KEY='true';
alter system set REMOVE_INACTIVE_STANDBY_TDE_MASTER_KEY='true'
                 *
ERROR at line 1: ORA-02065: illegal option for ALTER SYSTEM