$ git clone -n https://src.fedoraproject.org/rpms/octave-dicom.git /var/lib/mock/f40-build-803280-144215/root/chroot_tmpdir/scmroot/octave-dicom
Cloning into '/var/lib/mock/f40-build-803280-144215/root/chroot_tmpdir/scmroot/octave-dicom'...
$ git fetch origin c72843fb9dc102cc1adc4749c78baf9d634eee37:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/octave-dicom
 * [new ref]         c72843fb9dc102cc1adc4749c78baf9d634eee37 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c72843f Add Packit config