While Facebook did reveal plans to release a political ad transparency tool ahead of the EU elections, Mozilla was concerned this would be the same as the ad archive site Facebook delivered to the US in 2018, complete with "simple keyword searches." This wouldn't live up to the EU's Code of Practice on Disinformation, Mozilla argued, and would prevent more advanced research.

The company said it had talked to Facebook about its views, but that it was "unable to identify a path" toward useful political ad data disclosures. It hoped that the Commission would bring up the issue with Facebook -- in other words, that it might pressure the social network into making changes.

You might not see Facebook change its mind in the near future. In a response to previous complaints, it contended that its approach to browser plugins was part of a "routine update" meant to thwart deceptive ad blockers and scrapers that would feed data to "bad actors." It believes it's protecting privacy, and it's not in a rush to implement anything that could undermine that protection.