Examine source code of Firefox sees meteors

{
  "theme": {
    "images": {
      "theme_frame": "firefoxmeteors.jpg"
    },
    "colors": {
      "frame": "#ff0000",
      "tab_background_text": "#fffb00"
    }
  },
  "version": "2.0",
  "name": "Firefox sees meteors",
  "manifest_version": 2,
  "description": "Firefox goes stargazing and catches a glimpse of some meteors!"
}