Off the top of my head, I’d guess it was symbolism of the “triune God” represented by three colossal Star Destroyers/one colossal asteroid. Coupled with an allusion to ancient Byzantium, used to symbolize Heaven the way it does in some of WB Yeats’ poetry; since Byzantum’s two major chariot teams bore the colors Green and Blue, with the Emperor usually bestowing favors on the Blues rather than the Greens. And related to other stuff in the Lucasfilm vaults that uses this symbolism, eg, perhaps some WILLOW sequels.
Other than that, I don’t really have any ideas.