public function getManualDbFile()
    {
        if (isset($this->manualDbFile)) {
            return $this->manualDbFile;
        }

        $files = ConfigPaths::getDataFiles(['php_manual.sqlite'], $this->dataDir);
        if (!empty($files)) {
            if ($this->warnOnMultipleConfigs && \count($files) > 1) {
                $msg = \sprintf('Multiple manual database files found: %s. Using %s', \implode($files, ', '), $files[0]);
                \trigger_error($msg, E_USER_NOTICE);
            }

            return $this->manualDbFile = $files[0];
        }
    }