It helps to prevent Facebook's tracking (doesn't stop, but helps stop), but it is missing a lot of Facebook URLs. It only has 3 of Facebook's URLs built in, but it is missing the URLs for threads, meta AI, whatsapp, all of the FB help and company pages, and their other projects. There is actually an issue and pull request open for this on their GitHub, but Mozilla seems to be ignoring it, and because of that, I have to take off major points, since they know about it, and someone is fixing it for them, but they still aren't doing anything about it, which is unfortunate.