In Transport manager, it is using this value in config to send email. It will be better if the secret key is stored in .env so that it will not be shared with others

protected function createMandrillDriver()
    {
        $config = $this->app['config']->get('services.mandrill', []);

        return new MandrillTransport(
            new HttpClient(Arr::get($config, 'guzzle', [])), $config['secret']
        );
    }

I think they were intentionally removed since mandrill is not used as much as it was before due to it no longer being free.

Ahh. I see. @taylorotwell actually clarified in here. Since Laravel is supporting it and most tutorials out there assumes the config.services is still accessing the secret key from the .env that only requires user to add secret key in .env , don't you think it is better to keep it for now to avoid error/confusions? Or maybe from the TransportManager#createMandrillDriver, get the secret key value directly from .env