So, how are we doing with this issue ?
I just installed Mojave on a brand-new SSD drive. I'm using the latest version of Opera. Passwords are not saved; on the pane that provides that part of the security package I have all options turned on. No passwords appear on the list.
I renewed (refreshed ? revived ?) Opera to obtain default settings. No success.
Has any new information surfaced on the issue of saved passwords ?