$ git clone -n https://src.fedoraproject.org/rpms/espresso.git /var/lib/mock/f42-build-3346790-45002/root/chroot_tmpdir/scmroot/espresso
Cloning into '/var/lib/mock/f42-build-3346790-45002/root/chroot_tmpdir/scmroot/espresso'...
$ git fetch origin d8a8a772727ae33106e94b537409f9e95c634c5c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/espresso
 * [new ref]         d8a8a772727ae33106e94b537409f9e95c634c5c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d8a8a77 Rebuild with gsl 2.8