Any news on this feature? I was about to create a feature request for this, although a bit different. I honestly don't care about file type, so it would be ok if it shows up for any kind of file.
In my case, not having this option became a problem because running a web app as a PWA created by Vivaldi won't show that dialog and will silently download the file to the default folder. No dialog, no notification, no nothing. Not even on the main window and regardless of download/notification settings.
I even reported it not triggering download as a bug because of the lack of visual clue. Now I know it does download, but it just doesn't tell you that. It just feels like there is a bug in the download button of the page I'm using in PWA form.
Making it ask for location by default would be a good workaround for PWA mode (or Shortcut mode. I don't remember how you call it. I can't find how to create these web apps anymore). I'm still going to create another better worded ticket when I get the time regarding PWA and download behaviour. The one I mentioned above was built from a misconception on my part (and bad UX on Vivaldi's part)