Examine source code of Four Colors

{
  "name": "Primary Colors",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "blue.jpg"
    },
    "colors": {
      "frame": "rgba(22, 93, 247, 1)",
      "tab_background_text": "rgba(242, 5, 5, 1)",
      "toolbar": "rgba(244, 252, 98, 1)",
      "bookmark_text": "rgba(242, 5, 5, 1)",
      "toolbar_field": "rgba(255, 255, 255, 1)",
      "toolbar_field_text": "rgba(36, 222, 16, 1)"
    }
  }
}