$ git clone -n https://src.fedoraproject.org/rpms/river.git /var/lib/mock/f41-build-854805-166967/root/chroot_tmpdir/scmroot/river
Cloning into '/var/lib/mock/f41-build-854805-166967/root/chroot_tmpdir/scmroot/river'...
$ git fetch origin 791d90795a53ada2c1e406a66c7b8d28299e4df5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/river
 * [new ref]         791d90795a53ada2c1e406a66c7b8d28299e4df5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 791d907 Update to 0.3.5 (#2299425)