Not sure, but the link was on OFTC.
Re:Wikimedia DNS
by extraduder_ire on Thursday September 07, 2023 @01:00AM
(#37414932)
They don't have an official one, but many de-facto rooms exist on other networks operated by volunteers. Mainly on Libera chat.
https://en.wikipedia.org/wiki/Wikipedia:IRC has more detail.
Does wikimedia have an IRC server?