$ git clone -n https://src.fedoraproject.org/rpms/ceph.git /var/lib/mock/f41-build-side-1-3132392-39648/root/chroot_tmpdir/scmroot/ceph
Cloning into '/var/lib/mock/f41-build-side-1-3132392-39648/root/chroot_tmpdir/scmroot/ceph'...
remote: warning: refname 'HEAD' is ambiguous.        
$ git fetch origin cbcfdf7b455bffdca634f8ad164cb8ce96cb6e66:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ceph
 * [new ref]         cbcfdf7b455bffdca634f8ad164cb8ce96cb6e66 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at cbcfdf7 ceph-19.2.0 scikit-learn -> scikit_learn  rhbz#2325990