At first I was not entirely sure of everything I did, but I quickly found my way around, and must say this addon + MacPass is an interesting alternative to well-known cloud-based password managers. It might be a bit more user friendly (being able to write new passwords/updated passwords from the browser would be excellent, particularly, and avoid the pain of manually reopening the password file and creating/updating the proper entry) and is not yet 100% out-of-the-way, but it's really close. I really appreciate the addon and I think there's still room for important features. However, the existing feature set is already really interesting and works really well.