@ppb1701 @joeo10 hello, I run Thunderbird. The AI is an experiment that is in an add-on. We are playing with the technology trying to figure out if there are any useful features worthwhile with it. We may never ship that add-on at all.
Thunderbird is forever free and open source, these services are optional, opt-in features that will always be an add-on. We are not going to force AI on anyone.