$ git clone -n https://src.fedoraproject.org/rpms/gsl.git /var/lib/mock/f41-build-850897-165761/root/chroot_tmpdir/scmroot/gsl
Cloning into '/var/lib/mock/f41-build-850897-165761/root/chroot_tmpdir/scmroot/gsl'...
$ git fetch origin e44bd42d08d93f25552aa322b9306e70775ca8b7:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gsl
 * [new ref]         e44bd42d08d93f25552aa322b9306e70775ca8b7 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e44bd42 Minor spec file cleanups