Comment 2 for bug 1616994

Earlier versions of Firefox used to have a similar functionality, implemented with a small window displayed for a short time on the desktop. This was removed in an effort to avoid these dialogs, that were likely perceived as obtrusive, and it was replaced with the current animation in the Downloads button in the toolbar.

Maybe we could consider reintroducing this if we had a different implementation, more integrated with the notifications offered by modern operating systems. However, it's unlikely that someone from design and engineering will be able to look at this in the short term.

I'll leave the bug open for future reference, but we need a design decision before we can accept code patches.