A simple one too - it would be on a 216 colour pallete using six values for each of R, G and B.
R = 1/5
G = 2/5
B = 3/5
Edit: of course that makes sense it is probably a "web safe" one
If it's such a simple combination, I wonder why it wasn't officially named until 2014. CSS has had names for all sorts of weird colors since forever.
Most CSS color names were inherited from the X11 color list [1], which, in turn, sourced its colors from a weird mixture of Crayola crayons, paint samples, and idiosyncratic personal choices [2]. It's a mess.