First off, I have appended a number of other rigged objects via 'Collections' to Blender files before and they worked as expected. I fact, this human figure was appended before. But, during the course of editing it in project appended into, I made a mess in a variety of ways, including not being about to unhide the armature. So deleted it and appended the figure again. Basically, I am in the same situation as before in that I see in the Outliner the armature, but cannot select it.