Examine source code of nitrogen

{
  "theme": {
    "images": {
      "theme_frame": "nitrogen1.jpg"
    },
    "colors": {
      "frame": "#121861",
      "tab_background_text": "#058015"
    }
  },
  "version": "2.0",
  "name": "nitrogen",
  "manifest_version": 2,
  "description": "atomic spectrum of nitrogen"
}