View file phpBB3/vendor/twig/twig/lib/Twig/Extension/Debug.php

<?php

use Twig\Extension\DebugExtension;

class_exists('Twig\Extension\DebugExtension');

@trigger_error('Using the "Twig_Extension_Debug" class is deprecated since Twig version 2.7, use "Twig\Extension\DebugExtension" instead.', \E_USER_DEPRECATED);

if (false) {
    /** @deprecated since Twig 2.7, use "Twig\Extension\DebugExtension" instead */
    class Twig_Extension_Debug extends DebugExtension
    {
    }
}