$ git clone -n https://src.fedoraproject.org/rpms/plasma-milou.git /var/lib/mock/f42-build-side-1-3566292-46733/root/chroot_tmpdir/scmroot/plasma-milou
Cloning into '/var/lib/mock/f42-build-side-1-3566292-46733/root/chroot_tmpdir/scmroot/plasma-milou'...
$ git fetch origin db8dd7a666b004b1158bed571927671d56e0f8b4:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/plasma-milou
 * [new ref]         db8dd7a666b004b1158bed571927671d56e0f8b4 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at db8dd7a 6.4.0