In my opinion this is a severe data loss. "Forget About This Site" doesn't delete bookmarks without a warning. And since saved passwords are more important (since if you loose them you may not be able to find them again) than bookmarks it…
The Toolkit password manager is responsible for remembering usernames and passwords (aka. logins) on sites and allowing the user to autofill or autocomplete it upon returning to the website.
Perhaps this might affect other sites out there that are using placeholders in their credential fields. STR: - visit facebook.com (make sure you have some logins saved) - right click on the "New Password" field and use "Fill Password" - the…