public function getConfigFile()
    {
        $configPath = $this->appDir . '/config/' . self::CONFIG_FILE . '.php';
        if (!file_exists($configPath)) {
            // Internal base config file
            $configPath = VENDOR_KNOB_BASE_DIR . '/src/config/' . self::CONFIG_FILE . '.php';
        }

        if (null === $this->config && file_exists($configPath)) {
            $this->config = require($configPath);
            static::replaceParameters($this->config);
        }

        return $this->config;
    }