$ git clone -n https://src.fedoraproject.org/rpms/ristretto.git /var/lib/mock/f42-build-side-1-3499865-45966/root/chroot_tmpdir/scmroot/ristretto
Cloning into '/var/lib/mock/f42-build-side-1-3499865-45966/root/chroot_tmpdir/scmroot/ristretto'...
$ git fetch origin 510670fadd4bc5a6900ea9566b67d4d62e30e5e9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ristretto
 * [new ref]         510670fadd4bc5a6900ea9566b67d4d62e30e5e9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 510670f Update to 0.13.4. Fixes rhbz#2355180