For those of you that don’t know, the Magento routeing system is largely based on classes provided by Zend Framework 1. Whilst browsing through the code I came across something interesting in the method Zend_Controller_Request_Http::setRequestUri. What was interesting to me, was that it prioritises two headers (HTTP_X_ORIGINAL_URL and HTTP_X_REWRITE_URL) over REQUEST_URI. Why is that interesting?