Item.php

<?php

namespace Drupal\Core\Render\Element;

use Drupal\Core\Render\Attribute\FormElement;

/**
 * Provides a display-only form element with an optional title and description.
 *
 * Note: since this is a read-only field, setting the #required property will do
 * nothing except theme the form element to look as if it were actually required
 * (i.e. by placing a red star next to the #title).
 */
class Item extends FormElementBase {
    
    /**
     * {@inheritdoc}
     */
    public function getInfo() {
        return [
            // Forms that show author fields to both anonymous and authenticated users
            // need to dynamically switch between #type 'textfield' and #type 'item'
            // to automatically take over the authenticated user's information.
            // Therefore, we allow #type 'item' to receive input, which is internally
            // assigned by Form API based on the #default_value or #value properties.
'#input' => TRUE,
            '#markup' => '',
            '#theme_wrappers' => [
                'form_element',
            ],
        ];
    }

}