How to show tooltips on form labels based on view filter descriptions in a Bootstrap sub-theme?
You can do it in form alter, here's an example (add additional conditions yourself):

/**
 * Implements hook_form_FORM_ID_alter().
 */
function yourmodule_form_views_exposed_form_alter(&amp;$form, &amp;$form_state, $form_id) {    
  $field_name = 'filter-title';
  $form['title']['#attributes'] = array(
    'data-toggle' =&gt; 'tooltip',
    'data-original-title' =&gt; $form['#info'][$field_name]['description']
  );
  $form['#info'][$field_name]['description'] = '';
}