Examine source code of Linear Donut

{
  "theme": {
    "images": {
      "theme_frame": "LinearDonut.jpg"
    },
    "colors": {
      "frame": "#1920e6",
      "tab_background_text": "#08042b"
    }
  },
  "version": "2.0",
  "name": "Linear Donut",
  "manifest_version": 2,
  "description": "A cool blue design with halftone dots"
}