$ git clone -n https://src.fedoraproject.org/rpms/nbdkit.git /var/lib/mock/f41-build-816982-150570/root/chroot_tmpdir/scmroot/nbdkit
Cloning into '/var/lib/mock/f41-build-816982-150570/root/chroot_tmpdir/scmroot/nbdkit'...
$ git fetch origin ce8ba94d2cb5d931916777be6eae27d17c786871:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/nbdkit
 * [new ref]         ce8ba94d2cb5d931916777be6eae27d17c786871 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ce8ba94 Fix tarball signature