Terrestrial-Foreunner Collusion

In For Love And Glory, IL, Lissa, Hebo and Dzesi are in their spaceship, Hulda, on a planetary surface near a Forerunner base but they do not venture out until L.

Lissa and Hebo figure the Terrestrial mental collective and the Forerunners are in cahoots. How do they figure?

The guardian ship:

spoke in the principle languages of all the current spacefaring races;

knew the capabilities of the human and Susaian ships, even including the details of their circuitry.

How could a Forerunner artifact have acquired such knowledge?

But why should the knowledge have come from Earth? Beyond this point, how they figure becomes obscure.

Hebo has recently been on Earth and says that it has become strange. Terrestrials are cooperative and unanimous in a way impossible anywhere else. Linked to a massive central AI, they retain individual personalities but are also in a "'...mental collective.'" (p. 275) If they are responsible for the guardian ship, then they have learned of the black hole collision from the Foreunners who would have arranged for not only observation stations but also space probes to be built on the planets of the giant star. Thus, Earth, interested in the collision, would not have needed to launch any probes of its own...

I keep hitting CapsLk instead of A so that, e.g., "strange" becomes "strNGE." I will have to return to the obscure figuring some time tomoz.