"No shady privacy policies or back doors for advertisers" proclaims the Firefox homepage, but that's no longer true in Firefox 128.
Less than a month after acquiring the AdTech company Anonym, Mozilla has added special software co-authored by Meta and built for the advertising industry directly to the latest release
Like when they announced they were working on it in 2022: https://blog.mozilla.org/en/mozilla/privacy-preserving-attribution-for-advertising/