If you dont care about Ad search engines, Studies, Pocket, Google Safebrowsing, search suggestions, a start page with ads, weak privacy settings, all cookies saved forever, no adblocking, a unique canvas fingerprint, a user agent containing your Linux Distro,…
I went through the arkenfox user.js and literally all of it minus 20 or so settings just make sense. The rest are kinda overkill, but really, Firefox is horrible out of the box.