Mixed feelings about Firefox Addons' new non-Recommended extensions warning
I don't look at addons on addons.mozilla.org very often, so I didn't know until now that Mozilla has started showing a warning on the page for many addons, such as Textern (currently), to the effect, well, let me just quote what I see now (more or less):
[! icon] This is not monitored for security through Mozilla's Recommended Extensions program. Make sure you trust it before installing.
(Textern is among the Firefox addons that I use.)
On the one hand, I can see why Mozilla is doing this. Even in their more limited WebExtensions form, Firefox addons can do a great deal of damage to the security and privacy of the people who use them, and Mozilla doesn't have the people (or the interest) to audit them all or keep a close eye on what they're doing. Firefox addons aren't quite the prominent target that Chrome addons are, but things like the "Stylish" explosion demonstrates that people are happy to target Firefox too. What happened with Stylish also fairly convincingly demonstrates that requiring people to approve addon permissions isn't useful in practice, for various reasons.
On the other hand, this is inevitably going to lead to two bad outcomes. First, some number of people will be scared away from perfectly fine addons that simply aren't popular enough for Mozilla to bring them into the Recommended Extensions program. The second order consequence is that getting people to use a better version of an existing addon has implicitly gotten harder if the existing addon is a 'Recommended Extension'; yours may be better, but it also has a potentially scary warning on it.
(Arguably this is the correct outcome from a security perspective; yours may be better, but it's not necessarily enough better to make up for the increased risk of it not being more carefully watched.)
Second, some number of people will now be trained to ignore another security related warning because in practice it's useless noise to them. I think that this is especially likely if they've been directly steered to an addon by a recommendation or plug from somewhere else, and aren't just searching around on AMO. If you're searching on AMO for an addon that does X, the warning may steer you to one addon over another or sell you on the idea that the risk is too high. If you've come to AMO to install specific addon Y because it sounds interesting, well, the warning is mostly noise; it is a 'do you want to do this thing you want to do' question, except it's not even a question.
(And we know how those questions get answered; people almost always say 'yes I actually do want to do the thing I want to do'.)
Unfortunately I think this is a case where there is no good answer. Mozilla can't feasibly audit everything, they can't restrict AMO to only Recommended Extensions, and they likely feel that they can't just do nothing because of the harms to people who use Firefox Addons, especially people who don't already understand the risks that addons present.