Config/app.php should not have environment dependent configurations.

That's what the .env file is for - for storing environment dependent values. You then reference those environment specific values using the env() helper function.

Anything that can change environment to environment should be stored and accessed in this way.

yes true. but still it could make a better experience for new comers like me to have providers and aliases in a separate file to avoid any confusions.

The providers and aliases are part of the app configuration, though. The only other value that would really change in the app config is the url, which is only really used for artisan commands, and can be set using the env() helper.

The information is quite clear in the documentation, so it shouldn't be confusing to newcomers, assuming the documentation is read. If it's not clear, however, perhaps suggest a PR to the docs or discuss it with the community to address any concerns.

Comments throughout Laravel's source and the documentation are amongst the best I've seen for most of the frameworks I've looked at, and the community itself is very good at helping each other out when questions arise that aren't covered by the docs, or aren't clear.

yes only a small change to be made in app.php.

'url' => 'http://localhost',

should change to

'url' => env('BASE_URL', 'http://localhost'),

May be it would help someone during configuration.

The "url" config option is used for Artisan commands when displaying the app link. That is not anything to do with the frontend base url (Apache/Nginx etc).