Yii use namespace 命名空间

return [
  'yiiaseAction' => YII2_PATH . '/base/Action.php',
  'yiiaseActionEvent' => YII2_PATH . '/base/ActionEvent.php',
  'yiiaseActionFilter' => YII2_PATH . '/base/ActionFilter.php',
  'yiiaseApplication' => YII2_PATH . '/base/Application.php',
  'yiiaseArrayAccessTrait' => YII2_PATH . '/base/ArrayAccessTrait.php',
  'yiiaseArrayable' => YII2_PATH . '/base/Arrayable.php',
  'yiiaseArrayableTrait' => YII2_PATH . '/base/ArrayableTrait.php',
  'yiiaseBehavior' => YII2_PATH . '/base/Behavior.php',
  'yiiaseBootstrapInterface' => YII2_PATH . '/base/BootstrapInterface.php',
  'yiiaseComponent' => YII2_PATH . '/base/Component.php',
 ......
];

namespace相当于Yii里面的别名，从上一段return的数组来看，可以把namespace抽象成array的key，然后根据key的值去计算获取value，value就是文件的绝对路径，Yii就帮你include