Class not found... So how do you extend the Yii2 widget class?

Question

Yii

I put the Breadcrumbs.php file into the components folder with the following content:

<?php
namespace app\components;
use yii\bootstrap\Html;
class Breadcrumbs extends \yii\widgets\Breadcrumbs
{
    ///
}

In the form I use the code:

<?php
use app\components\Breadcrumbs;
echo Breadcrumbs::widget([]);

Resulting in an error:
PHP Fatal error: Uncaught Error: Class 'app\components\Breadcrumbs' not found in ...

Answer 1

In the error app\components1
In the code namespace app\components;
something is wrong here