Wikipedia
XChat
XChat is an Internet Relay Chat (IRC) client. It has a choice of a tabbed document interface or tree interface, support for multiple servers, and numerous configuration options. Both command line and graphical versions were available.
XChat is available for Unix-like systems; derivatives with native support for OS X's Aqua interface are also available ( see below). A Windows port called XChat-WDK was created then discontinued in 2012, with its development moving largely to forks such as HexChat. XChat has not received software updates since 2012.