$ git clone -n https://src.fedoraproject.org/rpms/plasma-oxygen.git /var/lib/mock/f42-build-881284-183509/root/chroot_tmpdir/scmroot/plasma-oxygen
Cloning into '/var/lib/mock/f42-build-881284-183509/root/chroot_tmpdir/scmroot/plasma-oxygen'...
$ git fetch origin 76afa552b9aad61a216ad565bc7c6e036d645b32:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/plasma-oxygen
 * [new ref]         76afa552b9aad61a216ad565bc7c6e036d645b32 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 76afa55 6.3.2