$ git clone -n https://src.fedoraproject.org/rpms/libnbd.git /var/lib/mock/f39-build-2352495-60194/root/chroot_tmpdir/scmroot/libnbd
Cloning into '/var/lib/mock/f39-build-2352495-60194/root/chroot_tmpdir/scmroot/libnbd'...
$ git fetch origin be0531484031fc9818c87d3acb0ff8f2054b618c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libnbd
 * [new ref]         be0531484031fc9818c87d3acb0ff8f2054b618c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at be05314 Remove patch already upstream