Networking source for new networking example

I am trying to write a networked application using the "new" networking example shown here: http://unity3d.com/support/resources/example-projects/networking-example

I am confused about what parts of the networking code are available and how to figure out what is being called by the script. For example, does the call to "Network.Connect" call something in RakNet or something in the "Master Server" package available here?: http://unity3d.com/master-server/index.html

I am interested in the UDP based networking approach, specifically I am interested in modifying what information is sent/received during the initial connection phase, and I am curious which bytes are written and what they correspond to. Are all UDP Clients of type UDPProxyClient?

Thank you so much for any help!