public function getManualDb()
    {
        if (!isset($this->manualDb)) {
            $dbFile = $this->getManualDbFile();
            if (\is_file($dbFile)) {
                try {
                    $this->manualDb = new \PDO('sqlite:' . $dbFile);
                } catch (\PDOException $e) {
                    if ($e->getMessage() === 'could not find driver') {
                        throw new RuntimeException('SQLite PDO driver not found', 0, $e);
                    } else {
                        throw $e;
                    }
                }
            }
        }

        return $this->manualDb;
    }