Sometimes you want to use exisiting translations for locales, which do not directly match.
An example would be a website targeting Germany (de_de), Austria (de_at) and Switzerland (de_ch, fr_ch, it_ch). Although you may have
exisiting translations for German (de), French (fr) and Italian (it), there are problems using it directly.
The number of languages supported by the standard CJuiDatePicker implementation is limited and the language code to use is different from the application's language code.
This Wiki shows how to improve on that.
When building PHP web applications you usually have to take care about defining and providing a consistent development and production environment for your team. This includes your application packages, PHP-extensions, database servers and often further components such as a mail server or workers.
One of the common requests I see in the forum is how to implement RBAC. While you can implement Yii 2's built-in RBAC, that might be too much for developers who are just starting with Yii 2 or have simpler needs. Sometimes you are looking for a fast solution and just want two flavors, user and admin. And even if you will eventually need more, you can use these methods as a starting point for developing your own features or move on to Yii 2's RBAC.