Examine source code of The Blue Marble

{
  "theme": {
    "images": {
      "theme_frame": "top.jpg"
    },
    "colors": {
      "frame": "#002bff",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "The Blue Marble",
  "manifest_version": 2,
  "description": "The famous Blue Marble photograph of earth on a milky way backdrop."
}