Music Controller - or - Media Controller. It tells you if it has no media, if there's one playing media, it then shows you this one. Else, you have more than one media currently playing and it then shows a list.
On Debian, the following packages are required.
- dde-dock-dev -> Interfaces for Deepin's dock plugins
- qtbase5-dev -> Qt Core and Qt Widgets, UI and interfaces
- libdframeworkdbus-dev -> MPRIS DBus API
- libdtkwidget-dev -> UI