Huggle is a popular tool intended for dealing with vandalism and other unconstructive edits on Wikimedia projects, written in C++ using the Qt framework.
HAN (Huggle antivandalism network) is an IRC based communication protocol used to exchange information about vandalism patrolling in between clients of Huggle or other tools.
The HAN window in Huggle should make a tone (maybe optional), when someone writes something, otherwise nobody noticed (me), when someone is writing something. This tone should be only used for user generated messages, not for automatic messages (from bots or information from clients, but only for real messages - the black ones).
The source code of Huggle can be found at http://github.com/huggle/huggle3-qt-lx
More information about hg can be found at http://enwp.org/WP:HG