This documentation describes, how the translation (localization) is implemented in this project.
The default and fallback language (locale) is defined in config/app.php: fallback_locale
This will be used when e. g. no user is authenticated during the HTTP request or when there does not exist a translation for the target language (locale) for a specific text. So instead of showing variable names, the fallback language (locale) will be presented.
All available languages (locales) are defined in laravel/lang/.
The database seeder LocalizationSeeder (LocalizationSeeder.php) defines which languages will be available in the user profile.
Each available language has a dedicated directory with multiple subdirectories and PHP files, which hold and define the actual translations.
Those subdirectories and PHP files should reflect the same structure as the actual views under laravel/resources/views/.
This project is using the standard Laravel localization, so you can check out the official documentation for further information: https://laravel.com/docs/10.x/localization