How WordPress sends emails using native mail() function, while function itself doesn’t work?

This question is more about PHP, rather than WP.

I call built-in function mail() on a hosting provider. It always returns FALSE, while on local machine it returns TRUE.

<?php

$result = mail(...);

var_dump($result) // always false on a provider machine;

So I know and expect that mail() shouldn’t work on a host machine. But when installing a WP from a package, it somehow sends “Welcome to WordPress” mail from the domain it runs on.

The core code of WP is a pure mess, and it’s not that easy to read and understand it. But when exploring it I noted that it uses mail() function to send welcome mails. So what I’m asking is how WP magically configures that mail() function to send mails?