ItemViewBuilder.php

<?php

namespace Drupal\aggregator;

use Drupal\Core\Entity\EntityViewBuilder;

/**
 * View builder handler for aggregator feed items.
 */
class ItemViewBuilder extends EntityViewBuilder {
    
    /**
     * {@inheritdoc}
     */
    public function buildComponents(array &$build, array $entities, array $displays, $view_mode) {
        parent::buildComponents($build, $entities, $displays, $view_mode);
        foreach ($entities as $id => $entity) {
            $bundle = $entity->bundle();
            $display = $displays[$bundle];
            // By default, the description field is exposed as a pseudo-field
            // rendered in this function. However it can optionally be rendered
            // directly using a field formatter. Skip rendering here if a field
            // formatter type is set.
            $component = $display->getComponent('description');
            if ($component && !isset($component['type'])) {
                $build[$id]['description'] = [
                    '#markup' => $entity->getDescription(),
                    '#allowed_tags' => _aggregator_allowed_tags(),
                    '#prefix' => '<div class="item-description">',
                    '#suffix' => '</div>',
                ];
            }
        }
    }

}