Return the main options, which are shown in the summary title.
public function buildOptionsForm_summary_options() {
$view_modes = entity_get_view_modes('node');
$options = array();
foreach ($view_modes as $mode => $settings) {
$options[$mode] = $settings['label'];
}
$options['title'] = t('Title only');
$options['default'] = t('Use site default RSS settings');
return $options;
}