ExperimentalModuleTestHooks.php

<?php

declare (strict_types=1);
namespace Drupal\experimental_module_test\Hook;

use Drupal\Core\Routing\RouteMatchInterface;
use Drupal\Core\Hook\Attribute\Hook;
use Drupal\Core\StringTranslation\StringTranslationTrait;

/**
 * Hook implementations for experimental_module_test.
 */
class ExperimentalModuleTestHooks {
    use StringTranslationTrait;
    
    /**
     * Implements hook_help().
     */
    public function help($route_name, RouteMatchInterface $route_match) : ?\Stringable {
        switch ($route_name) {
            case 'help.page.experimental_module_test':
                // Make the help text conform to core standards.
                return $this->t('The Experimental Test module is not done yet. It may eat your data, but you can read the <a href=":url">online documentation for the Experimental Test module</a>.', [
                    ':url' => 'http://www.example.com',
                ]);
        }
        return NULL;
    }

}