$ git clone -n https://src.fedoraproject.org/rpms/s3cmd.git /var/lib/mock/f40-build-2233313-53371/root/chroot_tmpdir/scmroot/s3cmd
Cloning into '/var/lib/mock/f40-build-2233313-53371/root/chroot_tmpdir/scmroot/s3cmd'...
$ git fetch origin eeeb73674acf0460c46c72b8ca7e1270ddb5a8b6:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/s3cmd
 * [new ref]         eeeb73674acf0460c46c72b8ca7e1270ddb5a8b6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at eeeb736 Upgrade to new upstream version