layout_builder_theme_suggestions_test.module

<?php


/**
 * @file
 * For testing theme suggestions.
 */


/**
 * Implements hook_theme().
 */
function layout_builder_theme_suggestions_test_theme() {
  // It is necessary to explicitly register the template via hook_theme()
  // because it is added via a module, not a theme.
  return [
    'field__node__body__bundle_with_section_field__default' => [
      'base hook' => 'field',
    ],
  ];
}

/**
 * Implements hook_preprocess_HOOK() for the list of layouts.
 */
function layout_builder_theme_suggestions_test_preprocess_item_list__layouts(&$variables) {
  foreach (array_keys($variables['items']) as $layout_id) {
    if (isset($variables['items'][$layout_id]['value']['#title']['icon'])) {
      $variables['items'][$layout_id]['value']['#title']['icon'] = [
        '#markup' => __FUNCTION__,
      ];
    }
  }
}