I don't know the source of this image, but it was posted in a MLP Facebook group and appears to be early material in designing G3 MLPs, specifically their colors.
It's interesting to see what changed! For example, on this chart Minty's hair is still green, like in her early prototype image. Applejack was at one point going to be spring green with white and pink hair! Some of the names were changed or never used, too. Sunny Daze was originally Sundance!
The codes like 245c are Pantone color codes which you can look up here. I think 'pearl' refers to the ponies' bodies being pearlescent.
Eight numbers are circled, and they coincide with the original eight G3 ponies. Although others of these ponies would appear in the toyline later.