Effects of culture
So the manual says about culture :
"When an
empire‘s culture is strong enough, a planet could even revolt and become neutral. You
can‘t colonize a neutral world that has revolved due to an enemy‘s cultural influence until
that influence is reduced. In addition to planetary effects, each race can unlock special
bonuses to its ships stationed in friendly culture."
What are those special bonuses ? I looks like the manual doesn't mention them explicitely.