Quoting the Wikipedia page (because the official site is gone):

Colloquy is an open-source IRC, SILC, ICB and XMPP[2] client for Mac OS X. Colloquy uses its own core, known as Chat Core, although in the past it used Irssi as its IRC protocol engine. One of the primary goals behind Colloquy was to create an IRC, SILC and ICB client with Mac OS X visuals. Colloquy contains a user interface that follows Apple’s Human interface guidelines in addition to containing support for traditional IRC command-line controls such as /nick and /join.

I contributed to this project back when I bought my first macOS laptop and decided to transition to this platform. At that time, I was an active member of the NetBSD project and took part in their developers-only chat room, which was (and probably still is) hosted on an ancient ICB server. There were no ICB clients for macOS at the time other than ircII and Irssi for the console.

WHat did I contribute?

Given that I really liked the macOS desktop environment and I wanted to have a “pure” macOS experience, I needed a native ICB chat client. Colloquy had a great UI and had a backend that allowed various protocols already, so “all” I had to do was extend this chat client to also support ICB. So I did. I had no previous knowledge of XCode nor Objective C and I gained some experience in both.

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