The Firefox Browser is a privacy nightmare on desktop and mobile 6 years ago
Yeah, but it doesn't record what the bookmark is or its URL, just that you opened a bookmark. Same thing with the new tabs. It doesn't record the login or password or the URL of the page you saved a password for. It doesn't record anything about your screenshots or downloads either, aside from the fact that you did it.
They are very openly using the least amount of data possible in order to know how people use the browser so that they know what to focus on to make things better, or what to fix that isn't working. They don't care who you are, all they want to know is how you are using their product so they can keep making it better.