Tkabber is a GUI client for XMPP (Jabber) instant messaging protocol. It provides full support of basic XMPP specifications as well as many protocol extensions (XEPs), such as multi-user conferencing, file transfers, extensive handling of privacy lists and much more. Tkabber is written in Tcl/Tk and thus is easily extensible.

Also a rich set of Tkabber external plugins is available in the package named "tkabber-plugins".