$ git clone -n https://src.fedoraproject.org/rpms/plasma-oxygen.git /var/lib/mock/f40-build-788836-135430/root/chroot_tmpdir/scmroot/plasma-oxygen
Cloning into '/var/lib/mock/f40-build-788836-135430/root/chroot_tmpdir/scmroot/plasma-oxygen'...
$ git fetch origin 969b325ee5c03ec094e19a7b796799c6c19fb2f9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/plasma-oxygen
 * [new ref]         969b325ee5c03ec094e19a7b796799c6c19fb2f9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 969b325 6.0.0