We don't know much about Border Worlds until WC4, and then we don't know much either.

In any case, before I (Monk) read the books by Peter Telep (Wing Commander and Pilgrim Stars), I was naively inspired by the idea of the Pilgrims and wrote a little paper about a possible ethnocultural background for Border Worlds that might still be doable without all the regrettable psychic stuff Telep imbued in his Pilgrims…