Resources to check how secure is your browser
Even when openning anonymous tabs, cleaning cookies or using VPN you still share some important information that might open your identity. List of resources below shows how easily attacker may receive information that you think should be actually hidden.
Detect your internal network IP address
Accurately get your location
ETag - might be used to uniquely identify you.
Is your browser safe against tracking
https://panopticlick.eff.org check that here.
Information about your browser and computer
https://whoer.net a lot of data including IP, language, screen resolution etc might be found here.
DNS exposes you IP
https://www.dnsleaktest.com even if you are using VPN.
Check your location with MAC of your router
http://samy.pl/mapxss/ just enter MAC address of your router and see whether it has this vulnerability.