I’m wondering what the differences between Librewolf and Firefox are, if you don’t use Arkenfox but only the recommended config on PrivacyGuides. How much of a difference is there privacy wise?
Clearly Librewolf is better in this case, and in my opinion it would be practically in the same position as FF with Arkenfox on Linux, but well, that’s my opinion, and I’m sure someone will say that I’m wrong and that FF without Arken is better than Librewolf. (Honestly, since I tried to at least mention Librewolf in the browsers section, I can’t stand this topic because of how ridiculous I find the opinion of some people about Librewolf, but anyway, I’ll give my opinion and help as much as I can).
By following our recommended configuration for Firefox, you’ll receive the most important benefits to privacy and security (i.e. enforcing HTTPS, sanitizing-on-close, and Strict ETP). Currently (and regardless of whether you use Arkenfox), we don’t recommend Librewolf.
In terms of the differences between Firefox and Librewolf, this comparison tool can give you an idea. Librewolf applies numerous further changes which improve security and benefit privacy (particularly by fooling naive fingerprinting scripts). We recommend the Arkenfox project for advanced users who are interested in further hardening.
I highly recommend reading this page of the Arkenfox wiki. It provides a great introduction to the benefits and drawbacks of further hardening (i.e. past our recommended configuration)!