Obviously this isn't a universe-shattering problem, but if the description of kde-plasma-addons in Synaptic had included a list of the contents, my original Synaptic search would have given the information I needed at a much earlier time. Some portmanteau packages do have this sort of list, and I wonder if it might be done more regularly to provide a better search facility in future?
BTW, congratulations to all who stitched the KDE upgrade to 4.8.3 into the normal Synaptic upgrade framework. In my case it ran like a dream and the forum provided all (well, nearly all!) the aid I needed to get everything running smoothly.