Laravel package development - How to install Illuminate Foundation without requiring laravel/framework?

I'm currently developing a Laravel package. The service provider of this package relies on magic methods config('my.config') and config_path('../my-config.php') defined in Illuminate/Foundation/helpers.php. PHPStorm notifies that it can't find these magic methods.

• How to make sure that these dependencies resolve?
• Is it possible to check which package installed a certain namespace in Composer?

Things I tried:

• The standalone package: https://packagist.org/packages/illuminate/foundation This package is apparently abandoned. No alternatives provided
• Install the entire laravel/framework. This conflicts with the application with which I try to install the package. I also want to avoid installing unnecessary dependencies in the package.
• I tried a bunch of packages from Illuminate: config, container and contracts. When I check the vendor folder, I don't see any foundation directory in the Illuminate directory

I have required the Laravel framework as a dev dependency instead.