layout_bg-8.x-1.0/layout_bg.module

<?php

/**
 * @file
 * Hooks for the layout_bg module.
 */

use Drupal\Core\Routing\RouteMatchInterface;

/**
 * Implements template_preprocess_hook().
 */
function template_preprocess_layout__layout_bg(&$variables) {
  if (isset($variables['content']['#base_layout_template'])) {
    $variables['base_layout_template'] = $variables['content']['#base_layout_template'];
  }
}

/**
 * Implements hook_theme().
 */
function layout_bg_theme() {
  return [
    'layout__layout_bg' => [
      'template' => 'layout--layout-bg',
      'render element' => 'content',
      'base hook' => 'layout',
    ],
  ];
}

/**
 * Implements hook_help().
 */
function layout_bg_help($route_name, RouteMatchInterface $route_match) {
  switch ($route_name) {
    case 'help.page.layout_bg':
      $output = '';
      $output .= '<h3>' . t('About') . '</h3>';
      $output .= '<p>' . t('Provides Layout plugins that feature
        a background region.') . '</p>';
      $output .= '<h3>' . t('Documentation') . '</h3>';
      $output .= '<p>' . t('For tips, examples, screenshots, use cases, etc: 
        <a href="https://www.drupal.org/docs/8/modules/layout-bg" target="_blank">
        Layout BG on Drupal.org</a>') . '</p>';
      return $output;

    default:
  }
}