(WebRTC leaks your local network IP, without any user interaction. This helps differentiate computers on a network/VPN. Here's a plugin which provides an easier way to toggle this off/on. https://github.com/ChrisAntaki/disable-webrtc-firefox)

Disable plugin & mimetype enumeration with plugins.enumerable_names=""

(Our browsers oftentimes have unique sets of plugins & mimetypes, when you factor in the version numbers. This helps differentiate specific browsers, on a network/VPN. Here's an addon which adds an easier way to toggle this off/on. https://github.com/ChrisAntaki/plugins-and-mimetypes-firefox)