Examine source code of Noctilucent clouds

{
  "theme": {
    "images": {
      "theme_frame": "Noctilucentcloudsfirefoxpersona.jpg"
    },
    "colors": {
      "frame": "#75c3ff",
      "tab_background_text": "#e0fcff"
    }
  },
  "version": "2.0",
  "name": "Noctilucent clouds",
  "manifest_version": 2,
  "description": "Noctilucent clouds seen in Sweden the summer of 2009."
}