Firefox should allow showing of a desktop notification when a download is complete

I think it would be really nice if like with other browsers Firefox would show a desktop notification using the style of the DE/OS when a download has been completed.

Currently one is required to install an add-on, but I think such basic functionality should really be built-in.

I originally made this request here: https://bugs.launchpad.net/ubuntu/+source/firefox/+bug/1616994 But thought I should also do so upstream.

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.

Any update on this?

*** Bug 1646450 has been marked as a duplicate of this bug. ***

This is still open for community pick, if someone would like to try providing a patch to add an optional system notification when downloads take more than a minute (thus it's more likely to miss their completion).
Then we could pass that proposal through UX for evaluation.