When I chanced upon the Orz, one of the dialogue options mentioned the Androsynth, or some other race. But I hadn't asked about that race; its name hadn't appeard on my Starmap where the Orz turned out to be stationed, so I shouldn't logically have had that option to ask.
I know that this would require a Boolean variable, perhaps called "Know-where-the-Androsynth-live" that would be carried everywhere just for this one line, but this is a notification of an improvement for somewhere along your to-do list.
Also, if you ask Commander Hayes about the Hierarchy while at the starbase, he'll mention that those are the Androsynth's home stars. It's a detail that's easily missable, but it's certainly there and accessable right at the beginning of the game. I assume this, plus the backstory, are why it was considered a given that the player would know.