Examine source code of Yellow by MaDonna

{
  "name": "Yellow by MaDonna",
  "manifest_version": 2,
  "version": "4.0",
  "theme": {
    "images": {
      "theme_frame": "YellowH.jpg"
    },
    "colors": {
      "frame": "rgba(250, 250, 70, 1)",
      "tab_background_text": "rgba(0, 0, 0, 1)",
      "toolbar": "rgba(247, 250, 70, 0)",
      "bookmark_text": "rgba(0, 0, 0, 1)",
      "toolbar_field": "rgba(250, 250, 70, 0.04)",
      "toolbar_field_text": "rgba(0, 0, 0, 1)",
      "tab_line": "rgba(0, 0, 0, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{62c7f316-cfdf-4750-b5fd-a2d88e14b4a9}"
    }
  }
}