Examine source code of My Normal Vision

{
  "theme": {
    "images": {
      "theme_frame": "01.jpg"
    },
    "colors": {
      "frame": "#274970",
      "tab_background_text": "#1b1e1f"
    }
  },
  "version": "2.0",
  "name": "My Normal Vision",
  "manifest_version": 2,
  "description": "Pure Firefox"
}