Examine source code of Twilight Horse

{
  "theme": {
    "images": {
      "theme_frame": "firefoxfin.jpg"
    },
    "colors": {
      "frame": "#00ff3c",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "Twilight Horse",
  "manifest_version": 2,
  "description": "Horse to the left and fireworks to the right"
}