Never seen anyone mention this:
Funnily enough, her version seems to be based not on Junior Murvin or the Clash, but a cover by somebody named J Boog.
I've been working on what/how she plays it with my guitar teacher (of Rudie Can't Fail fame, if you've ever explored playing Clash songs), and he says she is really doing some interesting stuff with her finger-picking.
Enjoy!
-c