Otherwise I'm not bothered. I won't be switching as long as this gets resolved within the next few days.
The cynical side of me says that it must not have this feature because if it did I'd have seen someone complaining about the browser "phoning home" or "forcing Mozilla's opinions into my eyeballs".
That said, I regularly get thinkpieces from Mozilla about the open internet, privacy, requests for donation (which I often oblige), etc., in my inbox. They also drop notifications under the address bar and in a "Message from Firefox" bar at the bottom of the new tab page, which I got the impression they had some live control over.
But maybe not, and/or maybe there's a long runway on preparing correspondence by any of these channels for some reason. If anything, I hope that when they do get around to getting some wide-reaching messaging out there, they indicate that they plan on doing the work to shorten the runway on emergency messaging in future.