The Radch's core isn't, but the empire built around it for protection is. Even I haven't been everywhere in it.

[This, at least, isn't the same kind of dangerous territory the other questions were, from the way Breq's shoulders relax. There's a method to the triggers, even though Lucretia doesn't know the reasoning behind it.]

There was variation in it, of course, but by their language, to become Radchaai is to become civilized, so there are certain commonalities no matter where in the Radch you go.