Why can't I change the contents of thankyou.php woocommerce?

Question

PHP

When placing an order, when I have already entered everything and clicked "pay", I go to this page:

I don't know how to change it. I found from the code that it lies in ../theme/woocommerce/checkout/thankyou.php
But even if the file is deleted in the theme and in the plugin, everything remains exactly in its place. I can't figure out where this bastard is. save)

Answer 1

All this was in the plugin folder:
Strange, inconvenient use of endpoints. But the answer is the answer