DateFormatAddForm.php

<?php

namespace Drupal\system\Form;

use Drupal\Core\Form\FormStateInterface;

/**
 * Provides a form for adding a date format.
 *
 * @internal
 */
class DateFormatAddForm extends DateFormatFormBase {
    
    /**
     * {@inheritdoc}
     */
    protected function actions(array $form, FormStateInterface $form_state) {
        $actions = parent::actions($form, $form_state);
        $actions['submit']['#value'] = $this->t('Add format');
        return $actions;
    }

}