Controllers extend a base class of Mage_Core_Controller_Varien_Action, which is a close copy of the Zend 
Framework class Zend_Controller_Action.


The double underscore method __ is a translation helper. This helper function is wrapped from almost any object 
context, which means you can safely call $this->__('My English Text') at almost any point in your code to translate a 
string. The htmlEscape function simply wraps PHP's native htmlspecialchars function, but it can also accept an 
array of data and escape each item individually.