Libnbd 1.18.0 added a new API feature, nbd_set_strict_mode(handle, LIBNBD_STRICT_AUTO_FLAG), but did not include any unit tests.  Since it is a new feature, QE would like to be able to test it.  Upstream added a unit test:
https://gitlab.com/nbdkit/libnbd/-/commit/54d4426394c372413f55f648d4ad1d21b3395e07
and it would be worth backporting that into RHEL (automatic if upstream releases 1.18.2 and RHEL rebases to that minor release, otherwise manually by an easy backport) to ease testing.