Yes it has gone somewhere else, but not as an entire block. All the info mentioned here should still be there, but distributed across a couple of paragraphs. The reason behind this is as follows:

If you look well, you see that this block first describes a concept (i.e. Agent object), then goes on to explain that description (the part about what inverse functional identifiers are) and then goes back to defining the original concept. In technical writing, at least the sort that I used to do, this was not considered optimum. This is why I separated the definition of inverse functional identifiers (second paragraph) and their listing (fourth paragraph).