layout_bg-8.x-1.0/examples/layout_bg_article_teaser/layout_bg_article_teaser.module

<?php

/**
 * @file
 * Hooks for layout_bg_article_teaser.
 */

/**
 * Implements hook_theme().
 *
 * If you were templating the teaser, you would probably put the
 * template in your theme. In this example, we are working within
 * a module so we need to use this hook.
 */
function layout_bg_article_teaser_theme() {
  $theme['node__article__layout_bg_teaser'] = [
    'template' => 'node--article--layout-bg-teaser',
    'base hook' => 'node',
  ];
  return $theme;
}