graphql.module

<?php

/**
 * Implements hook_help().
 */
function graphql_help($routeName) {
  if ($routeName !== 'help.page.graphql') {
    return;
  }

  $title = t('About');
  $description = t('
<p>This module generates and exposes a
  <a href="http://graphql.org/" target="_blank">GraphQL</a> schema for
  <a href="https://www.drupal.org/8" target="_blank">Drupal 8</a> entities,
  and allows you to expose your own custom schema in a consistent way and with
  minimal effort.</p>');

  $help = <<<EOT
<h3>$title</h3>
$description
EOT;

  return $help;
}

/**
 * Implements hook_theme().
 */
function graphql_theme() {
  return [
    'page__graphql_explorer' => [
      'render element' => 'elements',
      'base hook' => 'block',
    ],
    'page__graphql_voyager' => [
      'render element' => 'elements',
      'base hook' => 'block',
    ],
  ];
}