On a fresh, new installation of Tor Browser v11.0.9, I noticed that even though Show alerts about passwords for breached websites in Tor Browser Preferences > Privacy & Security is disabled by default:
Tor Browser still tries to connect to
firefox.settings.services.mozilla.com on startup:
According to Firefox own Help Docs How to stop Firefox from making automatic connections and Turn off website breach alerts, this shouldn't be happening.
This bug seems to persist in Tor Browser 12.0.4 too, and now it also seems to phone Securedrop.org on startup:
Bug still persists in Tor Browser 12.0.6: