What is a controller in Opencart?

Question

opencart

Hello guys. There is a problem. I'm quite new. Installed callback module. And there he writes this:
Insert the code into the controller file (.php):

$formcreator = new formcreator($this->registry); $data['formcreator_id127'] = $formcreator->initFeedback(127);

Paste in the template file (.twig) the following code:
{{ formcreator_id127 }}

What is a controller? Where is he located?

Answer 1

/catalog/controller
/admin/controller
The controller is the link between the view and the model.
If my memory serves me right, if you want to call a button in the footer, then you need to find the controller responsible for the footer. Attach a line to it and call the method in the template in the right place (basement).