Where is the controller for sending a letter to email called?

Question

opencart

Tell me where is the controller for sending a letter to email in opencart called?
There is a catalog/controller/account/forgotten.php controller responsible for password recovery
After entering the email, a password reset link comes to the mail, but I can’t understand where the catalog/controller/mail/forgotten.php controller is called

Answer 1

but I can't figure out where the controller is called catalog/controller/mail/forgotten.php

There is no explicit call.
It is called through the event system.

Answer 2

In what sense "in what place it is caused"?
You go to /index.php?route=account/forgotten
and this account/forgotten controller is triggered: it

is responsible for rendering the page and receiving data from the form.
The Mail class itself is here: