$ git clone -n https://src.fedoraproject.org/rpms/jackson-core.git /var/lib/mock/f40-build-2392486-60527/root/chroot_tmpdir/scmroot/jackson-core
Cloning into '/var/lib/mock/f40-build-2392486-60527/root/chroot_tmpdir/scmroot/jackson-core'...
$ git fetch origin 48532055f8e208103e26dbe4d9bb095329550d35:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/jackson-core
 * [new ref]         48532055f8e208103e26dbe4d9bb095329550d35 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4853205 Rebuild