$ git clone -n https://src.fedoraproject.org/rpms/nebula.git /var/lib/mock/f39-build-1815088-41837/root/chroot_tmpdir/scmroot/nebula
Cloning into '/var/lib/mock/f39-build-1815088-41837/root/chroot_tmpdir/scmroot/nebula'...
$ git fetch origin 63137600d8b1b9b469ba74c31e36cde3577eb4d6:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/nebula
 * [new ref]         63137600d8b1b9b469ba74c31e36cde3577eb4d6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6313760 Make it safer