The straight forward way is to look into the source code of the color extension where you'll find
colors: {
Apricot: "#FBB982",
Aquamarine: "#00B5BE",
Bittersweet: "#C04F17",
Black: "#221E1F",
Blue: "#2D2F92",
BlueGreen: "#00B3B8",
BlueViolet: "#473992",
BrickRed: "#B6321C",
Brown: "#792500",
BurntOrange: "#F7921D",
CadetBlue: "#74729A",
CarnationPink: "#F282B4",
Cerulean: "#00A2E3",
CornflowerBlue: "#41B0E4",
Cyan: "#00AEEF",
Dandelion: "#FDBC42",
DarkOrchid: "#A4538A",
Emerald: "#00A99D",
ForestGreen: "#009B55",
Fuchsia: "#8C368C",
Goldenrod: "#FFDF42",
Gray: "#949698",
Green: "#00A64F",
GreenYellow: "#DFE674",
JungleGreen: "#00A99A",
Lavender: "#F49EC4",
LimeGreen: "#8DC73E",
Magenta: "#EC008C",
Mahogany: "#A9341F",
Maroon: "#AF3235",
Melon: "#F89E7B",
MidnightBlue: "#006795",
Mulberry: "#A93C93",
NavyBlue: "#006EB8",
OliveGreen: "#3C8031",
Orange: "#F58137",
OrangeRed: "#ED135A",
Orchid: "#AF72B0",
Peach: "#F7965A",
Periwinkle: "#7977B8",
PineGreen: "#008B72",
Plum: "#92268F",
ProcessBlue: "#00B0F0",
Purple: "#99479B",
RawSienna: "#974006",
Red: "#ED1B23",
RedOrange: "#F26035",
RedViolet: "#A1246B",
Rhodamine: "#EF559F",
RoyalBlue: "#0071BC",
RoyalPurple: "#613F99",
RubineRed: "#ED017D",
Salmon: "#F69289",
SeaGreen: "#3FBC9D",
Sepia: "#671800",
SkyBlue: "#46C5DD",
SpringGreen: "#C6DC67",
Tan: "#DA9D76",
TealBlue: "#00AEB3",
Thistle: "#D883B7",
Turquoise: "#00B4CE",
Violet: "#58429B",
VioletRed: "#EF58A0",
White: "#FFFFFF",
WildStrawberry: "#EE2967",
Yellow: "#FFF200",
YellowGreen: "#98CC70",
YellowOrange: "#FAA21A"
},