Help finding waypoint in tracker php

I try to dig in the piwik php-stuff.
The entry is the piwik.php file. Unfortunately php itself is very messie with the “one class-one file” rule. So I can’t find the waypoint where php differentate between a trackPageview, ping and trackEvent. Evenso I notice that the javascript request is not sending a module-name.
Thanks in advance for any hint.