system/classes/Redirect.php
public function url($url = null, $append = '')
    {
        unset($_POST);
        unset($_FILES);
        header('location: '.$this->getRedirect($url).$append);
        exit;
    }
public function url($url = null, $append = '')
    {
        unset($_POST);
        unset($_FILES);
        header('location: '.$this->getRedirect($url).$append);
        exit;
    }
Redirects the browser.