modules/locale/views_handler_argument_locale_group.inc

<?php

class views_handler_argument_locale_group extends views_handler_argument {
  function construct() {
    parent::construct('group');
  }

  function summary_name($data) {
    return $this->locale_group($data->{$this->name_alias});
  }

  function title() {
    return $this->locale_group($this->argument);
  }

  function locale_group($group) {
    $groups = module_invoke_all('locale', 'groups');
    // Sort the list.
    asort($groups);
    return isset($groups[$group]) ? $groups[$group] : t('Unknown group');
  }
}