Firefox is a black box because you can't opt out of stuff before you click the 'update browser!' button. They've added default-on data harvesting, telemetry, ads, and now chatbots to Firefox that you have to track down and disable every time it happens. All self-updating software is a "black box" like this, but Mozilla has lost my trust that their updates will have more good than bullshit. So now I use Waterfox and don't need to worry that there's some new scheme to monetize me every time I get a browser update.