src/base/Commands.php
public static function setDefaultAction(string $prefix, string $name)
    {
        Yii::$app->controllerMap[$prefix]['defaultAction'] = $name;
    }
public static function setDefaultAction(string $prefix, string $name)
    {
        Yii::$app->controllerMap[$prefix]['defaultAction'] = $name;
    }
@deprecated 1.2.0 No longer recommended, use ActionGroup::setDefaultAction() instead

@param string $prefix
@param string $name