PackageKit is a service that hangs out and checks for updates. On openSUSE is a SystemD service so it runs in the background. This is a nice, neat automated solution to ensure that your system stays up to date.

You can read more about it here from Wikipedia 

For some, this does not work well for them. They don’t want the service running and would prefer to do updates manually.

If this annoys you feel free to stop and disable packagekit.

sudo systemctl stop disable packagekit

Should you decide that you miss it and long for the return of the notifications on your desktop it is just as easy to start and enable it.

sudo systemctl start enable packagekit

Further Reading