Laravel - Package Development - Default Package Configuration

You may also merge your own package configuration file with the application's published copy. This will allow your users to define only the options they actually want to override in the published copy of the configuration file. To merge the configuration file values, use the mergeConfigFrom method within your service provider's register method.

The mergeConfigFrom method accepts the path to your package's configuration file as its first argument and the name of the application's copy of the configuration file as its second argument:

     * Register any application services.
     * @return void
    public function register()
            __DIR__.'/../config/courier.php', 'courier'
This method only merges the first level of the configuration array. If your users partially define a multi-dimensional configuration array, the missing options will not be merged.