farm-2.x-dev/modules/core/map/farm_map.module

<?php

/**
 * @file
 * The farm_map module.
 */

/**
 * Implements hook_theme().
 */
function farm_map_theme($existing, $type, $theme, $path) {
  return [
    'farm_map' => [
      'variables' => [
        'attributes' => [],
      ],
    ],
  ];
}