Having some sort of Q&A/wiki page is on my list. If you have specific questions you can always post them at https://github.com/kkapsner/CanvasBlocker/issues

Some sites do not use fingerprinting. That's why the icon is green and no notifications show up. But keep in mind that not all notifications mean that a fingerprint is generated. Also legit use of the APIs can trigger the notification. It's just an indicator that CB did something.