As written on the API docs: An Action Provider Widget is a widget that has declared several actions by using its 'public static function actions()'. After, a Controller can easily import all its declared actions on its 'public function actions()'.
After you have setup your Yii2 advanced application, you now have setup your user authentication for both frontend and backend. However, if you have first logged into frontend, and try to access backend from the same client machine, you see no login screen, but find yourself automatically logged in.
This Behaviour helps to view time/date/timestamp/datetime from db to local Date / Time / Date Time format and in local Timezone. And save into db in with db timezone and db format. You only need to include this behaviour in models where need this facility.