Sorry, I get tunnel vision sometimes .. 🙂
I don't trust password managers, so I made my own, and don't let the browser keep any passwords at all.

    qk4-li3 The one I made for myself keeps an encrypted sqlite database, it'll retrieve a list of headers, and then only open the db when it needs to retrieve data under a header, and then immediately close. If you'd like to try it out, it's stand alone and portable, but I make no guarantees since I made it for me 🙂
    https://drive.proton.me/urls/5JTC4S1SJM#QsZVlakxclIq

        qk4-li3 Harvey Ok. It's no good then.

        But you never store passwords in your browser, right? So it wouldn't make a difference for your use case.

        One thing... I DON'T have any passwords stored in vivaldi. I never store any passwords in my browser.

            BloodFeastMan That's clever. Very nice of you to make such offer, thank you. I think that I don't have much use for it personally though. Still, nice gesture.

              Staudey But you never store passwords in your browser, right? So it wouldn't make a difference for your use case.

              That's right and it's great to have options then! Maybe I'll at least try it.

              So... something sudo-ing with .desktop files - ...now where's my vivaldi .desktop file? - found it... now what... erm... help!...
              How do I change startup script for my browser? What's proper way to do it?

                  qk4-li3 Note that whenever making changes to the desktop files you should copy the desktop file from /usr/share/applications/ to ~/.local/share/applications and then make your edits to the copy. Files in /usr/share/applications are managed by the package manager and your changes will be overwritten on a package update (which are frequent with Vivaldi). DEs will ignore desktop entries in /usr/share/applications if a file exists in ~/.local/share/applications with the same name. Note that you might need to fix the desktop file if it becomes incompatible with the application, there's no mechanism for syncing just a few changes to it. When you're done making changes to the local copy run update-desktop-database ~/.local/share/applications to make your DE pick up your changes.

                    qk4-li3 In the .desktop file, there are lines:

                    [Desktop Entry]
                    Version=1.0
                    Type=Application
                    Name=<name>
                    Comment=<not needed but whatever>
                    Exec=<THIS IS WHERE YOU PUT YOUR COMMAND LINE REVISION>
                    Icon=<some icon>
                    Path=<not needed for a web browser>
                    Terminal=false
                    StartupNotify=true

                    Hope this helps!

                      This (/usr/bin/vivaldi-stable %U --password-store=basic) modified startup script with additional command line argument or whatchamacallit* seems to work: auto-login on, no pop-ups when opening vivaldi. - *I'm not programming literate.

                      Thank you again @ReillyBrogan for an excellent answer and detailed and responsible instructions!
                      @BloodFeastMan Yes, good example is always helpful! Thank you very much.

                      For others, who may also bump their heads at this, I also found:

                      https://chromium.googlesource.com/chromium/src/+/HEAD/docs/linux/password_storage.md

                      If I'm not mistaken, this functionality is same with chromium based browsers, which Vivaldi also is.

                      Now then, do I keep it this way? I doubt it. Reason being that after a month, do I remember that I made this modification? Am I always careful to notice, if there's some another kind of deceiving wording used, when prompt storing password, like "Remember Me" or "Keep Me Logged In" etc.? Is there a tick box? Is it empty? If it's empty, then what? Is it already ticked? Then what? meh...