ActionAddForm.php

<?php

namespace Drupal\action\Form;

use Drupal\Core\Form\FormStateInterface;

/**
 * Provides a form for action add forms.
 *
 * @internal
 */
class ActionAddForm extends ActionFormBase {
    
    /**
     * {@inheritdoc}
     *
     * @param array $form
     *   An associative array containing the structure of the form.
     * @param \Drupal\Core\Form\FormStateInterface $form_state
     *   The current state of the form.
     * @param string $action_id
     *   The action ID.
     */
    public function buildForm(array $form, FormStateInterface $form_state, $action_id = NULL) {
        $this->entity
            ->setPlugin($action_id);
        // Derive the label and type from the action definition.
        $definition = $this->entity
            ->getPluginDefinition();
        $this->entity
            ->set('label', $definition['label']);
        $this->entity
            ->set('type', $definition['type']);
        return parent::buildForm($form, $form_state);
    }

}