$ git clone -n https://src.fedoraproject.org/rpms/alglib.git /var/lib/mock/f41-build-side-1-2771913-32257/root/chroot_tmpdir/scmroot/alglib
Cloning into '/var/lib/mock/f41-build-side-1-2771913-32257/root/chroot_tmpdir/scmroot/alglib'...
$ git fetch origin eeebdfacf488870528df5826672c7986511c6d4d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/alglib
 * [new ref]         eeebdfacf488870528df5826672c7986511c6d4d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at eeebdfa Fix %files