The Civilization Trial has developed to the point where the vast majority of civilizations keep a certain level of observation on other civilizations in the starry sky.
Even though setting out for the starry sky isn't easy, observation doesn't require very powerful technology.
Take No.2 Planet, for example.
This is a planet slightly smaller than the Human Mother Planet, with a volume of about three-quarters of that of the Human Mother Planet. The civilization on it is a species that calls itself "Mongolian."
