Doesn't exist. The digits only go from 0-9, A-F. g and v are not included in those ranges. It looks like you pressed random buttons.
Those letters and numbers you see there are hexidecimal numbers, 3 of them grouped to be exact. FF = 255. 0F = 15. Etc.
Three groups of 2 digits, meaning each color value can go from 0-255.
R = Red
G = Green
B = Blue
FFFFFF is 255 red, 255 green, and 255 blue, which makes white.
8888FF is 136 red, 136 green, and 255 blue, which makes a bright blue.
It's not like mixing colors in real life, as a digital green is a primary color instead of the real yellow being one. Red and green strangely make yellow, where they would probably produce a rather nasty result in real life.