Textual: IRC for Mac OS X
www.codeux.com/textual
From the page
Saved with the link. Notes from 2007 to 2016 are mostly the page's own words, so this is probably an excerpt.
Textual is a lightweight IRC client created specifically for Mac OS X. It was designed with simplicity in mind. Textual has taken the best of IRC and built it into a single client. Its easy-to-use functionality combined with scripting support makes it an ideal IRC client for novice to advanced users.