protected function getFilenameArray()
    {
        $table = DataObject::singleton(File::class)->baseTable();
        // Convert original query, ensuring the legacy "Filename" is included in the result
        /** @skipUpgrade */
        return $this
            ->getFileQuery()
            ->dataQuery()
            ->selectFromTable($table, ['ID', 'Filename'])
            ->execute()
            ->map(); // map ID to Filename
    }