Sabine is described as skilled with both paint and explosives. (She's also described as "feisty," but considering that the last revealed character was "the muscle," I can't complain - they're going for easily identifiable types on purpose at this point.)
"She's adding something that we really haven't seen in Star Wars before," said Joel Aron, Co-Supervisor of Lighting and VFX, in the video from Hollywood Reporter. "You have a character that is expressive and creative through art."
The last artist I can think of in the Star Wars world was the musician Juval Charn in Shadow Games, a book which left me wishing that her art was more a part of her story.
|Rebels concept art|
(As an aside: Sabine introduces herself as "Specter Five"- I wonder if the whole team will have code names?)
Satine is played by Tiya Sircar, who also voice-acted in Walking With Dinosaurs 3D and Phineas and Ferb and acted in films and TV including 17 Again.
The Hollywood Reporter piece is a bittersweet reveal, as the two girls are the last two characters to be officially announced, and Disney put out a press release at the International Toy Fair that aimed Rebels toys squarely at "the boys' aisle."