What are the .primary and .secondary colors in SwiftUI?

In the new SwiftUI, the type Color is very similar to UIColor from UIKit.

There are the common colors, as expected, but there is the addition of two other colors that I noticed:

• .primary
• .secondary

There is nothing in the Apple Documentation for the descriptions of the different Colors.

• What are these colors?
• Which one should I use for certain things?

Pre defined colors:

extension Color {
     
    // MARK: - Text Colors
    static let lightText = Color(UIColor.lightText)
    static let darkText = Color(UIColor.darkText)
    static let placeholderText = Color(UIColor.placeholderText)

    // MARK: - Label Colors
    static let label = Color(UIColor.label)
    static let secondaryLabel = Color(UIColor.secondaryLabel)
    static let tertiaryLabel = Color(UIColor.tertiaryLabel)
    static let quaternaryLabel = Color(UIColor.quaternaryLabel)

    // MARK: - Background Colors
    static let systemBackground = Color(UIColor.systemBackground)
    static let secondarySystemBackground = Color(UIColor.secondarySystemBackground)
    static let tertiarySystemBackground = Color(UIColor.tertiarySystemBackground)
    
    // MARK: - Fill Colors
    static let systemFill = Color(UIColor.systemFill)
    static let secondarySystemFill = Color(UIColor.secondarySystemFill)
    static let tertiarySystemFill = Color(UIColor.tertiarySystemFill)
    static let quaternarySystemFill = Color(UIColor.quaternarySystemFill)
    
    // MARK: - Grouped Background Colors
    static let systemGroupedBackground = Color(UIColor.systemGroupedBackground)
    static let secondarySystemGroupedBackground = Color(UIColor.secondarySystemGroupedBackground)
    static let tertiarySystemGroupedBackground = Color(UIColor.tertiarySystemGroupedBackground)
    
    // MARK: - Gray Colors
    static let systemGray = Color(UIColor.systemGray)
    static let systemGray2 = Color(UIColor.systemGray2)
    static let systemGray3 = Color(UIColor.systemGray3)
    static let systemGray4 = Color(UIColor.systemGray4)
    static let systemGray5 = Color(UIColor.systemGray5)
    static let systemGray6 = Color(UIColor.systemGray6)
    
    // MARK: - Other Colors
    static let separator = Color(UIColor.separator)
    static let opaqueSeparator = Color(UIColor.opaqueSeparator)
    static let link = Color(UIColor.link)
    
    // MARK: System Colors
    static let systemBlue = Color(UIColor.systemBlue)
    static let systemPurple = Color(UIColor.systemPurple)
    static let systemGreen = Color(UIColor.systemGreen)
    static let systemYellow = Color(UIColor.systemYellow)
    static let systemOrange = Color(UIColor.systemOrange)
    static let systemPink = Color(UIColor.systemPink)
    static let systemRed = Color(UIColor.systemRed)
    static let systemTeal = Color(UIColor.systemTeal)
    static let systemIndigo = Color(UIColor.systemIndigo)

}

Visual colors representation in light and dark modes:

Code used to generate color pallet:

var body: some View {
    VStack {
        HStack {
            Text("Light")
                .frame(width: 75, height: 40)
            Text("Dark")
                .frame(width: 75, height: 40)
        }
        List(CC.colors, id: \.name) { color in
            HStack {
                Text(color.name)
                    .frame(width: 300, alignment: .trailing)
                Rectangle()
                    .environment(\.colorScheme, .light)
                    .frame(width: 75, height: 40)
                    .foregroundColor(color.color)
                    .border(Color.black, width: 3)
                Rectangle()
                    .environment(\.colorScheme, .dark)
                    .frame(width: 75, height: 40)
                    .foregroundColor(color.color)
                    .border(Color.black, width: 3)

            }
        }
        //PlacesListView(places: placesViewModel.places, htmlAttributions: placesViewModel.htmlAttributions)
    }
    .navigationTitle("Places")
   // .embedInNavigationView()
}

And color list are taken from the FarouK answer.

struct CC {
    let name: String
    let color: Color

    static var colors: [CC] { [
        CC(name: "lightText", color: .lightText),
        CC(name: "darkText", color: .darkText),
        CC(name: "placeholderText", color: .placeholderText),
        CC(name: "label", color: .label),
        CC(name: "secondaryLabel", color: .secondaryLabel),
        CC(name: "tertiaryLabel", color: .tertiaryLabel),
        CC(name: "quaternaryLabel", color: .quaternaryLabel),
        CC(name: "systemBackground", color: .systemBackground),
        CC(name: "secondarySystemBackground", color: .secondarySystemBackground),
        CC(name: "tertiarySystemBackground", color: .tertiarySystemBackground),
        CC(name: "systemFill", color: .systemFill),
        CC(name: "secondarySystemFill", color: .secondarySystemFill),
        CC(name: "tertiarySystemFill", color: .tertiarySystemFill),
        CC(name: "quaternarySystemFill", color: .quaternarySystemFill),
        CC(name: "systemGroupedBackground", color: .systemGroupedBackground),
        CC(name: "secondarySystemGroupedBackground", color: .secondarySystemGroupedBackground),
        CC(name: "tertiarySystemGroupedBackground", color: .tertiarySystemGroupedBackground),
        CC(name: "systemGray", color: .systemGray),
        CC(name: "systemGray2", color: .systemGray2),
        CC(name: "systemGray3", color: .systemGray3),
        CC(name: "systemGray4", color: .systemGray4),
        CC(name: "systemGray5", color: .systemGray5),
        CC(name: "systemGray6", color: .systemGray6),
        CC(name: "separator", color: .separator),
        CC(name: "opaqueSeparator", color: .opaqueSeparator),
        CC(name: "link", color: .link),
        CC(name: "systemRed", color: .systemRed),
        CC(name: "systemBlue", color: .systemBlue),
        CC(name: "systemPink", color: .systemPink),
        CC(name: "systemTeal", color: .systemTeal),
        CC(name: "systemGreen", color: .systemGreen),
        CC(name: "systemIndigo", color: .systemIndigo),
        CC(name: "systemOrange", color: .systemOrange),
        CC(name: "systemPurple", color: .systemPurple),
        CC(name: "systemYellow", color: .systemYellow)]
    }
}

extension Color {
     
    // MARK: - Text Colors
    static let lightText = Color(UIColor.lightText)
    static let darkText = Color(UIColor.darkText)
    static let placeholderText = Color(UIColor.placeholderText)

    // MARK: - Label Colors
    static let label = Color(UIColor.label)
    static let secondaryLabel = Color(UIColor.secondaryLabel)
    static let tertiaryLabel = Color(UIColor.tertiaryLabel)
    static let quaternaryLabel = Color(UIColor.quaternaryLabel)

    // MARK: - Background Colors
    static let systemBackground = Color(UIColor.systemBackground)
    static let secondarySystemBackground = Color(UIColor.secondarySystemBackground)
    static let tertiarySystemBackground = Color(UIColor.tertiarySystemBackground)
    
    // MARK: - Fill Colors
    static let systemFill = Color(UIColor.systemFill)
    static let secondarySystemFill = Color(UIColor.secondarySystemFill)
    static let tertiarySystemFill = Color(UIColor.tertiarySystemFill)
    static let quaternarySystemFill = Color(UIColor.quaternarySystemFill)
    
    // MARK: - Grouped Background Colors
    static let systemGroupedBackground = Color(UIColor.systemGroupedBackground)
    static let secondarySystemGroupedBackground = Color(UIColor.secondarySystemGroupedBackground)
    static let tertiarySystemGroupedBackground = Color(UIColor.tertiarySystemGroupedBackground)
    
    // MARK: - Gray Colors
    static let systemGray = Color(UIColor.systemGray)
    static let systemGray2 = Color(UIColor.systemGray2)
    static let systemGray3 = Color(UIColor.systemGray3)
    static let systemGray4 = Color(UIColor.systemGray4)
    static let systemGray5 = Color(UIColor.systemGray5)
    static let systemGray6 = Color(UIColor.systemGray6)
    
    // MARK: - Other Colors
    static let separator = Color(UIColor.separator)
    static let opaqueSeparator = Color(UIColor.opaqueSeparator)
    static let link = Color(UIColor.link)
    
    // MARK: System Colors
    static let systemBlue = Color(UIColor.systemBlue)
    static let systemPurple = Color(UIColor.systemPurple)
    static let systemGreen = Color(UIColor.systemGreen)
    static let systemYellow = Color(UIColor.systemYellow)
    static let systemOrange = Color(UIColor.systemOrange)
    static let systemPink = Color(UIColor.systemPink)
    static let systemRed = Color(UIColor.systemRed)
    static let systemTeal = Color(UIColor.systemTeal)
    static let systemIndigo = Color(UIColor.systemIndigo)

}