What is the address in the DepDrop widget?

Question

Yii

I ran into a problem, I can’t understand what kind of url the link in the documentation indicates the DepDrop widget. It as I understand record to the table which is in model? or something I missed?

echo $form->field($model, 'subcat')->widget(DepDrop::classname(), [
    'options'=>['id'=>'subcat-id'],
    'pluginOptions'=>[
        'depends'=>['cat-id'],
        'placeholder'=>'Select...',
        'url'=>Url::to(['/site/subcat'])
    ]
]);

Answer 1

Good evening.
Read
And so, site - controller, subcat - action

Answer 2

This is a link to a controller action that returns the data that will be displayed in the dropdown list. Used for ajax data loading