AppController.phpに[ var $components = array(‘DebugKit.Toolbar’);]の一文を追加したら、
DebugKit is not installed. It will help you inspect and debug different aspects of your application. You can install it from GitHub
↑このエラーが消えて、
↓このエラーが出てきました。

Missing Plugin
Error: The application is trying to load a file from the DebugKit plugin
Error: Make sure your plugin DebugKit is in the app/Plugin directory and was loaded
<?php
CakePlugin::load('DebugKit');
Loading all plugins: If you wish to load all plugins at once, use the following line in your app/Config/bootstrap.php file
CakePlugin::loadAll();
Notice: If you want to customize this error message, create app/View/Errors/missing_plugin.ctp
これはパス誤りだったようで、Plugin/DebugKit にあったのですが、 app/Plugin/DebugKitにディレクトリ毎移動させる事でエラーが消えました。
参考サイト様
![CakePHP立ち上げエラー[The application is trying to load a file from the DebugKit pluginとMake sure your plugin DebugKit is in the app/Plugin directory and was loaded]](https://normalblog.net/system/wp-content/uploads/2015/11/cakephp.png)

