$ git clone -n https://src.fedoraproject.org/rpms/ghc-mwc-random.git /var/lib/mock/f40-build-2117947-50725/root/chroot_tmpdir/scmroot/ghc-mwc-random
Cloning into '/var/lib/mock/f40-build-2117947-50725/root/chroot_tmpdir/scmroot/ghc-mwc-random'...
$ git fetch origin 693689ac6489eab56d1314c105eab40d7cbfdfc6:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-mwc-random
 * [new ref]         693689ac6489eab56d1314c105eab40d7cbfdfc6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 693689a bump release