Recs.
Updated
The Firefox web browser distributed by the Mozilla Foundation has long offered its own IRC client as a browser add-on (Chatzilla), driven by the foundation's long history of using an in-house IRC network (MozNet) as the primary means of communication throughout their hierarchy. When Firefox abandoned their XUL add-on format with the release of Firefox Quantum, several forks of the project (Pale Moon, Waterfox, Basilisk, Interlink) were made in protest of the negative privacy implications of the new add-on format and Ambassador is a Chatzilla fork to continue to produce an IRC Client add-on for their users in addition to a standalone version that can run outside of a web browser.
SpecsUpdate
Pros
Pro Wrapping IRC client inside web browser provides natural workflow
So much of the purpose for any interpersonal communication is wrapped up in exchanging knowledge and sharing experiences with IRC being no different. The modern era has taken us to a place where a large portion of what we want to share and exchange with others are things which require the internet and a web browser, so when links are inevitably traded on IRC, the ability to interact with them natively in another tab of the same application has become one of the most productive ways to use IRC.