Since it got removed in the recent knot release. See: https://github.com/CZ-NIC/knot/commit/a6971a4025133a77b29f6d2b381b40dc0499730c
Since it got removed in the recent knot release. See: https://github.com/CZ-NIC/knot/commit/a6971a4025133a77b29f6d2b381b40dc0499730c