It's a really interesting detail that the UC simply assumed that the FC were also doing xenowarfare research and used it as a justification for pumping greater funding into their own. There are numerous examples from the Cold War where the US or the Soviets fell down a research rabbit hole because of some capability they assumed the other had -- even though they didn't. The "bomber gap" and the F-15 come to mind.
When the FC violated the Nairon Treaty both Factions took the opportunity to add another system to their fold at some point in I believe the Vanguard quest line they mention establishing the forward operating base on Toliman that grew into the city of Londinion.
