To quote a comment on HN about it:

"'It’s obvious this violates both the so-called "Cookie Law" and the Google Analytics ToS, as both require any page with tracking to specifically tell the user that they will track the user. And the so-called "Cookie Law" goes even further, and requires it to be directly done in a modal.

How did Mozilla, a company saying they fight for privacy, approve something that does not even meet the absolute minimum bar for privacy, the actual privacy laws?"