Super simple theme-less phpBB 3.x plug-in

<?
// phpBB initialization
define('IN_PHPBB', true);
$phpbb_root_path = (defined('PHPBB_ROOT_PATH')) ? PHPBB_ROOT_PATH : './';
$phpEx = substr(strrchr(__FILE__, '.'), 1);
include($phpbb_root_path . 'common.' . $phpEx);
$user->session_begin();
$auth->acl($user->data);

// require user to be logged in
if (!$auth->acl_gets('u_viewprofile', 'a_user', 'a_useradd', 'a_userdel'))
{
    if ($user->data['user_id'] != ANONYMOUS)
    {
        trigger_error('NO_VIEW_USERS');
    }

    login_box('', ((isset($user->lang['LOGIN_EXPLAIN_' . strtoupper($mode)])) ? $user->lang['LOGIN_EXPLAIN_' . strtoupper($mode)] : $user->lang['LOGIN_EXPLAIN_MEMBERLIST']));
}

// My code
echo 'Hello '.$user->data['username'];
echo ' (User ID '.$user->data['user_id'].")<br>\n";
?>