What does this mean? cake mix

[Heaven]

I found this recipe on the taste website:

Ingredients (serves 8)

• 125g fresh or frozen raspberries
• 370g packet rich chocolate cake mix
• 2 eggs
• 1/2 cup sour cream
• 2 tablespoons milk
• cocoa powder, to serve

Method

1. Preheat oven to 180°C. Grease and line a 20cm (base) round cake pan.
2. Mash raspberries with a fork. Set aside.
3. Using an electric mixer, beat cake mix, eggs, sour cream and milk until just combined. Increase speed to medium and beat for 2 minutes.
4. Spoon mixture into prepared cake pan. Drop spoonfuls of raspberries over cake. Using a knife, swirl berries through mixture.
5. Bake for 40 to 45 minutes or until a skewer inserted into the centre comes out clean. Cool in pan for 10 minutes. Turn onto a wire rack. Dust with cocoa to serve.

What does '370g packet rich chocolate cake mix' mean?? Any cake mix? And you don't make it like the pack says, you just use the dry ingredients and add what this recipe says?