Ok... so it sould be
```
function mica_studies_export_menu_local_tasks_alter(&$data, $router_item, $root_path) {
  $links = array();
  if ($root_path === 'node/%') {
    $node = $router_item['map']['1'];
    if($node->type === 'study' && mica_export_can_export_node($node)) {
      $links['export-study-xml'] = array(
        '#theme' => 'menu_local_action',
        '#weight' => 50,
        '#link' => array(
          'title' => t('Export'),
          'href' => 'node/' . $node->nid . '/export-xml'
        ),
      );
    }
  }
  $data['actions']['output'] = array_merge($data['actions']['output'], $links);
}
```