Son para escapar los valores en las vistas (phtml) utilizando htmlspecialchars o htmlentities mediante el método escape().
Cita: Encoding to use with htmlentities() and htmlspecialchars(). Escapes a value for output in a view script. Encoding to use in escaping mechanisms; defaults to latin1 (ISO-8859-1).
If escaping mechanism is one of htmlspecialchars or htmlentities, uses setting.