Where is the sending of a letter to the buyer called in Opencart3?

Question

opencart

In theory, in the checkout / confirm controller, but I did not find a call to the method of sending a letter in it. As I understand it, \catalog\controller\mail\
order.php is responsible for sending mail to the client and the admin, but I can’t understand where and how it is called.

Answer 1

in the troika it is rendered in events