dektrium\rbac\models\Permission::getUnassignedItems PHP Method

    public function getUnassignedItems()
    {
        return ArrayHelper::map($this->manager->getItems(Item::TYPE_PERMISSION, $this->item !== null ? [$this->item->name] : []), 'name', function ($item) {
            return empty($item->description) ? $item->name : $item->name . ' (' . $item->description . ')';
        });
    }