But, it's not a build dependency of #Plasma-workpace , apparently, so the #BackportsPPA for #KDE doesn't need to include the #KUserFeedback library, but will pick it up if it already exists.

Recently the PPA updated to 5.18.1 and now systemsettings5 has the entry for User Feedback without my needing to rebuild it and plasma-workspace from source.

So, that's a bonus (:*