Most people will not know what "IRC" is, so if the link in the footer is there with the intent of bringing people into IRC to chat with us, it would make far more sense to call it "Chat" rather than "IRC".
Similar to how we link to our forums as "Forums" and not as "community" (way to vague) or "Discourse" (specific to the technology and may change over time, and historically has).
Or how we link to the ticket tracker as "Bug Tracker" rather than "tickets" (what?) or "JIRA" (again, specific to technology and has changed historically and may change again).
See also mfmeulenbelt’s comments on the forum: https://community.metabrainz.org/t/idea-rename-irc-to-chat/450955?u=freso