This WIP project from 2009 attempted to rewrite the Matchserver/Locator from MAIET entertainment's GunZ: The Duel. It has been dead for some time now.
Below is the original README from the project on ragezone:
This is the very, very work-in-progress alpha release of the Team Zebra Gunz emulator. We've just barely begun work so obviously it has no features that any non-developers would be interested in. It's more just a proof-of-concept than anything and a way to give the community a chance to contribute something of their own to this little project. It's coded in C#, which seems handy since a lot of people here know C# or are learning it.
As of now, only the encryption is implemented, as well as a few simple data structures. It encrypts/decrypts packets correctly, initializes the key correctly, etc. We've just now begun to look at the way the protocol is structured, since a lot of things about the packets have changed since we all last looked at them. We'll probably make another update to this release once we can get into the lobby and get chat working, since that will prove real progress. Hopefully this will be within the next few days, we all have busy lives though, so we'll see.