Add way to change audio output (speakers vs headphones) on a per application basis
As far as I know, it is not possible to change the audio output on a per application basis from anywhere in gnome-shell. An external application (e.g. pavucontrol) is required.
Such a normal task, however, shouldn't require third party applications. It is unreasonable to think that a normal user would want to have Spotify on his speakers and a Discord call in his earbuds? As a matter of fact, everyone else has this feature built-in (e.g. Windows, OSX, Plasma, don't know about MATE, XFCE and LXQt). But why should gnome require an external application/extension?
My suggestion is to add a dropdown in the sound settings or expand the functionality provided by the user-menu volume indicator: maybe instead of muting on click, something kind of stupid in my opinion, it would expand to a sub menu, like this extension.