This doesn't appear to have an official entry within addons.mozilla.org/firefox
The addon configuration screen takes an unusual amount of time to open.
On restart, it will pop up a configuration dialog.
- SSL Observatory. While I don't like the idea of sending information, being able to confirm certificates with an outside is handy. Enabled.
On restart, it will open a new tab with https://www.eff.org/https-everywhere/faq