Where are the "versions"?

There are several ways. First, you can open the Repository Files view from any component and select the file and run the Show History action. Of if you have already loaded a repository workspace, select any file in RTC from the resource navigator or package explorer and select "Team > Show History".

We cover a lot of this in the tutorials and articles at:

https://jazz.net/learn/LearnItem.jsp?href=content/docs/source-control/index.html

It may be useful to have a read, we tried to cover most of the SCM concepts you need to get started.

I had read all that material already and ran the tutorial to.

I still fail to see what "version" in particular a stream or workspace is seeing. Well, I can tell that the current version in the History tab is bolded, which is a good indication of the current version. But the version identification is not displayed anywhere; something like 1.1.4.5, or /<stream>/<revision>, or whatever revision format is being used by RTC.

I am looking for a "label" (not to confuse with a ClearCase label) that uniquely and unambiguously identifies each element version throughout the history, so that one can say "hey, look at foo.java version x.y.z, there is something fishy about it". I cannot see that right now in the History View.

We don't have that kind of label for either file versions or change-sets, you would instead say "do you have the change-set from Joe that he delivered today at 2pm?", or "do you have the file version created by Joe at 3pm today"?