class RobotListBuilder

class RobotListBuilder extends ConfigEntityListBuilder {
    use DescriptionTemplateTrait;
    
    /**
     * {@inheritdoc}
     */
    protected function getModuleName() {
        return 'config_entity_example';
    }
    
    /**
     * Builds the header row for the entity listing.
     *
     * @return array
     *   A render array structure of header strings.
     *
     * @see \Drupal\Core\Entity\EntityListController::render()
     */
    public function buildHeader() {
        $header['label'] = $this->t('Robot');
        $header['machine_name'] = $this->t('Machine Name');
        $header['floopy'] = $this->t('Floopy');
        return $header + parent::buildHeader();
    }
    
    /**
     * Builds a row for an entity in the entity listing.
     *
     * @param \Drupal\Core\Entity\EntityInterface $entity
     *   The entity for which to build the row.
     *
     * @return array
     *   A render array of the table row for displaying the entity.
     *
     * @see \Drupal\Core\Entity\EntityListController::render()
     */
    public function buildRow(EntityInterface $entity) {
        $row['label'] = $entity->label();
        $row['machine_name'] = $entity->id();
        $row['floopy'] = $entity->floopy;
        return $row + parent::buildRow($entity);
    }
    
    /**
     * Adds some descriptive text to our entity list.
     *
     * Typically, there's no need to override render(). You may wish to do so,
     * however, if you want to add markup before or after the table.
     *
     * @return array
     *   Renderable array.
     */
    public function render() {
        $build = $this->description();
        $build[] = parent::render();
        return $build;
    }

}