Feature_window_functions counts queries, not functions

ariaDB [test]> show status like 'Feature_window_functions';

+--------------------------+-------+

| Variable_name            | Value |

+--------------------------+-------+

| Feature_window_functions | 0     |

+--------------------------+-------+

1 row in set (0.00 sec)

MariaDB [test]> select rank() over (order by a), row_number() over (partition by b) from t1;

Empty set (0.00 sec)

MariaDB [test]> show status like 'Feature_window_functions';

+--------------------------+-------+

| Variable_name            | Value |

+--------------------------+-------+

| Feature_window_functions | 1     |

+--------------------------+-------+

1 row in set (0.00 sec)

MariaDB [test]> show status like 'Feature_subquery';

+------------------+-------+

| Variable_name    | Value |

+------------------+-------+

| Feature_subquery | 0     |

+------------------+-------+

1 row in set (0.00 sec)

MariaDB [test]> select (select 1), (select 2);

+------------+------------+

| (select 1) | (select 2) |

+------------+------------+

|          1 |          2 |

+------------+------------+

1 row in set (0.00 sec)