SUMMARY
With the new notification system, notifications from Cantata Music Player (e.g. new song playing) are not complying with the new specifications: Cantata does not appear in the list of applications to be configured and notifications belonging to Cantata are not grouped together in the history as they should.

STEPS TO REPRODUCE
1. From Plasma 5.16 Beta
2. Play some music from Cantata, wait for a few songs to play (or jump to new tracks?)
3. Look into notifications history and notifications configuration.

OBSERVED RESULT
Cantata notifications are not grouped together as they should. Also, Cantata does not appear in the list of configurable applications (e.g. to make the notifications not appear in history).


EXPECTED RESULT
Notifications should be grouped and Cantata should be available in the applications list to modify the notifications behaviour.

SOFTWARE/OS VERSIONS
Operating System: openSUSE Leap 15.0
KDE Plasma Version: 5.15.90
KDE Frameworks Version: 5.58.0
Qt Version: 5.12.3
Kernel Version: 4.12.14-lp150.12.61-default
OS Type: 64-bit