fortnox-8.x-1.x-dev/modules/fortnox_credentials/fortnox_credentials.module

<?php

/**
 * @file
 * Custom functionality for fortnox_credentials module.
 */

/**
 * Implements hook_theme().
 */
function fortnox_credentials_theme($existing, $type, $theme, $path) {
  $theme = [
    'credentials' => [
      'path' => $path . '/templates',
      'template'  => 'credentials',
      'render element' => 'content',
    ],
  ];

  return $theme;
}