http://us63bgjkxwpyrpvsqom6kw3jcy2yujbplkhtzt64yykt42ne2ms7p4yd.onion/graves/news/2019-03-27-firefox_lockbox.html
Anyway, what I really wanted to do here was to analyze if the Lockbox is as private as they claim. Fortunately, Mozilla has graciously provided us a simple document showing exactly what data is collected, so let's use it. From https://lockbox.firefox.com/privacy.html (archive) : Credential data.