On the island of Viridis, which is Grace's adopted homeland, green is the faction color of the rabbit kingdom. So it's kind of rare to see a fox wearing it, because they have their own kingdom. However, since Grace's mistress Fiachra is a rabbit, and since her daughter with Fiachra is a princess of the rabbit kingdom, she thought she'd just slip on this lovely, and tight, green sweater to show where her loyalties lie.
This was a little freebie from Vespur to celebrate opening a new account. If ya like it, and wanna try for one yourself, go check things out here: http://www.furaffinity.net/journal/7808146/