IRC nickname in Discourse profile

I just noticed that there is a way to set my IRC nickname in my Discourse settings. I can see that it shows up in my card when clicking on my icon in a thread (not useful in my case). Is it used for anything else?

By the way the instructions below this field still mention Freenode while we moved to Libera.

AFAIK that’s just informational and is being done with custom user profile fields, that can be configured in the Discourse backend. Admins can add arbitrary fields there.