I didn't mention the cookie because it's not part of the protocol. It's how Google's servers behave. We don't know what the NK server does. According to Mozill

I didn't mention the cookie because it's not part of the protocol. It's how Google's servers behave. We don't know what the NK server does. According to Mozilla... Firefox is open source, you know. Even if you can't read C++ or understand the Bugzilla comments, you can also just Wireshark it.