$ git clone -n https://src.fedoraproject.org/rpms/libtdb.git /var/lib/mock/f42-build-side-1-3585707-46907/root/chroot_tmpdir/scmroot/libtdb
Cloning into '/var/lib/mock/f42-build-side-1-3585707-46907/root/chroot_tmpdir/scmroot/libtdb'...
$ git fetch origin caaaa29029a918903752c65c8f01fa16f781a103:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libtdb
 * [new ref]         caaaa29029a918903752c65c8f01fa16f781a103 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at caaaa29 Package LICENSE file