$ git clone -n https://src.fedoraproject.org/rpms/golang-github-d5-tengo-2.git /var/lib/mock/f42-build-867093-174628/root/chroot_tmpdir/scmroot/golang-github-d5-tengo-2
Cloning into '/var/lib/mock/f42-build-867093-174628/root/chroot_tmpdir/scmroot/golang-github-d5-tengo-2'...
$ git fetch origin f24dd0d33687833a97e772b06728bea4e40d6d1c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/golang-github-d5-tengo-2
 * [new ref]         f24dd0d33687833a97e772b06728bea4e40d6d1c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f24dd0d Update to latest upstream release (closes rhbz#2225845)