When using themes you want to changes some of the translations specifically to the theme while keeping the standard translations for most of the text.
Duplicating the main translation file is a headache for maintainance.
This how to provides a solution.
To secure your database from inconsistencies resulting from failing (complex) operations, you (should) use transactions.
However, complex methods often rely on other complex methods that themselves build on transactions.
This HowTo presents a method to nest or embed transactions without relying on the database's nesting capabilities.
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.