Yii 3 and many Yii 2 package sources are contained within
src directory which is convenient since you have less directories to check.
The Problem: Yii2 utilizes by default UserIdentity configured in config/web.php for connection, this object appy one table to authentication ('identityClass' => 'app\painel\models\User'). How to authentication from diferent tables? Solution: Create instances in web.php to uses UserIdentify. eg:
bad design of Active Record.