$ git clone -n https://src.fedoraproject.org/rpms/sylpheed.git /var/lib/mock/f40-build-2330431-59006/root/chroot_tmpdir/scmroot/sylpheed
Cloning into '/var/lib/mock/f40-build-2330431-59006/root/chroot_tmpdir/scmroot/sylpheed'...
$ git fetch origin 4abe6bc4969aecb04feea5269e1d815a5eb51c34:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/sylpheed
 * [new ref]         4abe6bc4969aecb04feea5269e1d815a5eb51c34 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4abe6bc spec modernization and small code fixes