Try IceCat. It's a GNU-approved Firefox clone (tracking Firefox codebase continuously), clean from integrations and pre-configured for privacy. It's also free, in both senses!
It tracks the Extended Support Release (ESR) branch of Firefox. That means it gets new features once a year and then only bugfixes after that. ESR 60 is last year's, work is probably ongoing to rebase IceCat on ESR 68 which came out last July.
