$ git clone -n https://src.fedoraproject.org/rpms/plasma-milou.git /var/lib/mock/f42-build-side-1-3585719-46907/root/chroot_tmpdir/scmroot/plasma-milou
Cloning into '/var/lib/mock/f42-build-side-1-3585719-46907/root/chroot_tmpdir/scmroot/plasma-milou'...
$ git fetch origin df19fe1fccc5b0cbcbf1aee666482f65069e69fe:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/plasma-milou
 * [new ref]         df19fe1fccc5b0cbcbf1aee666482f65069e69fe -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at df19fe1 6.4.2