UrlPlainFormatter.php

<?php

namespace Drupal\file\Plugin\Field\FieldFormatter;

use Drupal\Core\Field\FieldItemListInterface;
use Drupal\file\FileInterface;

/**
 * Plugin implementation of the 'file_url_plain' formatter.
 *
 * @FieldFormatter(
 *   id = "file_url_plain",
 *   label = @Translation("URL to file"),
 *   field_types = {
 *     "file"
 *   }
 * )
 */
class UrlPlainFormatter extends FileFormatterBase {
    
    /**
     * {@inheritdoc}
     */
    public function viewElements(FieldItemListInterface $items, $langcode) {
        $elements = [];
        foreach ($this->getEntitiesToView($items, $langcode) as $delta => $file) {
            assert($file instanceof FileInterface);
            $elements[$delta] = [
                '#markup' => $file->createFileUrl(),
                '#cache' => [
                    'tags' => $file->getCacheTags(),
                ],
            ];
        }
        return $elements;
    }

}