$ git clone -n https://src.fedoraproject.org/rpms/nbdkit.git /var/lib/mock/f41-build-855712-167324/root/chroot_tmpdir/scmroot/nbdkit
Cloning into '/var/lib/mock/f41-build-855712-167324/root/chroot_tmpdir/scmroot/nbdkit'...
$ git fetch origin e874463cba64ae9e55c656f1ed2ef2fdfcbaf044:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/nbdkit
 * [new ref]         e874463cba64ae9e55c656f1ed2ef2fdfcbaf044 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e874463 New upstream stable branch version 1.40.4