I'm logged in on "Joe's MacBook Pro" at a public Wi-Fi.
I get an alert window (apparently from no program in particular). It says:
Your Apple ID is now being used for iMessage and FaceTime on a new Mac.
If you recently signed into “Joe's MacBook Pro” you can ignore this notification.
What does this mean? I use several development tools (Emacs, …) but neither iMessage nor FaceTime.
I never use the same password twice as suggested as an answer to FaceTime hijacked, nor do I otherwise have a reason to believe my Apple (macOS or iCloud) account is compromised.
Is this a security risk? The message does not indicate what to do if I had not "recently signed into".
Please provide some back-up or reference for your answer, so as not to trigger extra caution when none is needed. The point is to understand what's happening, not to be prudent just to be on the safe side.