Firefox addons are reviewed, though as others note the process is a bit opaque. Interestingly, sometimes a release is approved, but then later someone comes back with issues. This is somewhat concerning as both a user and a dev. For users, it means there may be rogue extensions out there that haven't been closely reviewed yet. And for devs, it's frustrating to have a release approved and then months later to get audited.
Chrome is getting more granular in their approval process, but it seems that they're still a bit behind.
Chrome is getting more granular in their approval process, but it seems that they're still a bit behind.