Thanks Fariz. The scales have been lifted from my eyes, at least partially.

Yes, the count that is displayed corresponds to the number of items in the query result.  The query result appears to correspond to the number of artifacts in the container plus the gross number of artifacts that might populate the containers to which links are being shown.  For example, I have a container that holds a single modeling project, and in another container I am showing the number of packages, qualified by a name pattern, that are owned by the modeling project. The query result in the Modeling Project container lists the Modeling Project itself plus all of the packages (32 of them) that are in the model, irrespective of the name pattern. The other container shows just the two packages that comply with the name pattern.  That container's count is similarly affected by the containers down the line.

So now I think I understand what the count is, but I don't understand why anyone would want to show that count.