[Phobophobia]

Between the several HN threads on this, this is just what I was missing. Thanks for clarifying it is the defaults which change. That is completely acceptable. It's like any other feature or aspect of FF that a developer can change.

[Althorion]

I don’t think restricting the changes to default settings is enough, you can still do quite a lot of malicious or just plain annoying things with that—for example, I didn’t change the default browser theme, but that doesn’t mean that I wouldn’t be pissed if it changed to an advertisement of any sort.

It gives the developers a great power—they can change applications behaviour outside typical venues for this. Most users expect an update to change things, but if my browser would start to behave erratically and I knew I haven’t updated it for a while, it would have send me on a wild goose chase for other things that I might have done that make my Firefox crash or whatever. It wouldn’t have occurred to me that some change to my settings was pushed without my knowledge.

We can only hope FF devs will use that power responsibly. It can be a nice feature or a complete nightmare. And I for one would very much welcome some kind of pushed notification about that (‘hey, there was a problem with this and that, so we changed that and this; here’s how you can revert the change if needed’).