How does the 'Ternary Operator' i.e. the 'conditional operator' work with the 'echo' statement since

I'm using PHP 7.3.6 on my laptop that runs on Windows 10 Home Single Language 64-bit operating system.

I've installed the latest version of XAMPP installer on my laptop which has installed the Apache/2.4.39 (Win64) and PHP 7.3.6

Today, I come across following code example from the PHP Manual :

<?php
  echo $some_var ? 'true': 'false'; // changing the statement around
?>

As per my knowledge and according to the following text from PHP Manual :

The expression (expr1) ? (expr2) : (expr3) evaluates to expr2 if expr1 evaluates to TRUE, and expr3 if expr1 evaluates to FALSE.

It's also a well-known fact that echo statement in PHP doesn't return any value.

So, in the code example mentioned above also echo statement must not be returning any value.

So, my question is as the echo statement never returns any value how does the ternary operator comes to know that expr1(i.e. the statement echo $some_var) has been evaluated to true or false and accordingly prints the output as true or false?