I really don't feel like having the debate as to whether its local or remote - both are quite compromiseable in terms of security.
I don't want to have this integration into my browser. I don't like Green Eggs and Ham, Sam I am. I do not want it this way or that, online or off. That is the goalpost I expect Mozilla to hit, based on their general vision.
If I want to have my browsing habits analyzed, I'd rather `cat` out the history file to a tool I wrote.
Mozilla being an entity historically predicated on better practices choosing to deal this way is highly unpleasant. And, on topic, RSS is a good open practice that should be kept. Mozilla's choice to axe RSS and keep Pocket seems to all be in the same vein.
The moment that thing is local your concerns are not valid anymore. If a local browsing habits file can be exploited your browsing habits could also be detected by other means. Like you yourself said, that is just included in your browsing history (stored anyway by default).
There is no point in expressing a dislike for a good solution when the thing they are doing does not at all conflict with their mission. Which is the thing with removing RSS support, but not with the site recommendation.
If your main concern - not wanting that your history is uploaded - is met by the great solution Mozilla seems to have found here, it would really be the right thing to accept that.
It doesn't spy on anyone and it's trivial to disable. Hard to do it better.
Google yourself how many times a disabled feature "accidentally" re-enabled(& tracked!) for providers' benefit. Throw Apple & Google un for the most nefarious "accidents". Or not... despite no proclamations of Moz employees posting (as of yesterday) this thread has the stink of astroturf.
I just want to set things straight. Bad mouthing Mozilla for something they have not done does not help discussing the decisions they take.
On tracking, well, you may always look the code. It's all client-side, I guess the most nefarious accident it could happen is you noticing the suggestion again and disabling it again.