Textfield.php

<?php

namespace Drupal\config_translation\FormElement;

use Drupal\Core\Language\LanguageInterface;

/**
 * Defines the textfield element for the configuration translation interface.
 */
class Textfield extends FormElementBase {
    
    /**
     * {@inheritdoc}
     */
    public function getTranslationElement(LanguageInterface $translation_language, $source_config, $translation_config) {
        return [
            '#type' => 'textfield',
        ] + parent::getTranslationElement($translation_language, $source_config, $translation_config);
    }

}