suggestions

/**
* Implements hook_theme_suggestions_HOOK_alter().
*/
function MYMODULE_theme_suggestions_form_element_alter(array &$suggestions, array $variables, $hook) {
 if ($variables['element']['#name'] === 'form3_1_pane[organizations]') {
   $suggestions

$webform_name = $variables['elements']['#configuration']['webform_id'];
if ($webform_name) {
  $suggestions[] = 'block__webform__' . $webform_name;
}