Drupal → Вывод псевдо-поля при просмотре материала

/**
 * Implements hook_entity_extra_field_info().
 */
function modulename_entity_extra_field_info() {
  $extra_fields = [];
 
  $extra_fields['node']['article']['display']['extra_field_author'] = [
    'label' => t('Author name'),
    'weight' => 0,
  ];
 
  return $extra_fields;
}
 
/**
 * Implements hook_ENTITY_TYPE_view(): node.
 */
function modulename_node_view(array &$build, NodeInterface $node, EntityViewDisplayInterface $display, $view_mode) {
  if ($node->bundle() == 'article' && $display->getComponent('extra_field_author')) {
    $build['extra_field_author'] = [
      '#markup' => $node->getOwner()->getDisplayName(),
    ];
  }
}

/**
 * Implements hook_field_extra_fields().
 */
function mymodule_field_extra_fields() {
  // 'node' - Entity type
  // 'article' - Bundle name
  // 'display' - 'display' or 'form'
  // 'mymodule_author' - Field name
  $extra_fields['node']['article']['display']['mymodule_author'] = array(
    'label' => t('Author'),            // Label
    'description' => t('Author name'), // Description
    'weight' => 0,                     // Default weight
  );
  return $extra_fields;
}
 
/**
 * Implements hook_node_view().
 */
function mymodule_node_view($node, $view_mode, $langcode) {
  static $extra_fields_info = array();
 
  $extra_field_cache_key = $node->type . ':' . $view_mode;
  if (!isset($extra_fields_info[$extra_field_cache_key])) {
    $extra_fields_info[$extra_field_cache_key] = field_extra_fields_get_display('node', $node->type, $view_mode);
  }
 
  if (!empty($extra_fields_info[$extra_field_cache_key]['mymodule_author']['visible'])) {
    $node->content['mymodule_author'] = array(
      '#markup' => '<b>Author</b>: ' . $node->name,
      '#weight' => $extra_fields_info[$extra_field_cache_key]['mymodule_author']['weight'],
    );
  }
}