Unn is a star system. It appears to have one single human-inhabited planet. They have TL4 technology and mostly live in one or two large cities. The planet has a very large amount of radioactive material on the surface, which can cause radiation burns.
The government is religious and extremely xenophobic. Even when they try to convert outsiders by sending them PDFs of their holy books they have viruses, which is counterproductive. At least some members of the civilization have cried out for help, apparently due to the high radiation levels.
The Unn government seems to have little in the way of military technology, and it's pretty useless against most TL4 civilizations. They refuse to let people acquire their radioactive material, apparently believing this to be holy.