$ git clone -n https://src.fedoraproject.org/rpms/ser2net.git /var/lib/mock/f40-build-804906-144643/root/chroot_tmpdir/scmroot/ser2net
Cloning into '/var/lib/mock/f40-build-804906-144643/root/chroot_tmpdir/scmroot/ser2net'...
$ git fetch origin dd6daff7771493478ad927070ecca40c845fe4d1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ser2net
 * [new ref]         dd6daff7771493478ad927070ecca40c845fe4d1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at dd6daff update to 4.6.1