CTparental is a free and open-source parental control tool used to control computer usage or internet browsing. It comes with a simple and easy-to-use web interface powered by a Lighttpd web server. The idea of CTparental tool comes from other tools such as, iptables, dnsmasq, and inguardian privoxy.
An ongoing comprehensive user.js template for configuring and hardening Firefox privacy, security and anti-fingerprinting - ghacksuserjs/ghacks-user.js