Examine source code of Simple Dark

{
  "theme": {
    "images": {
      "theme_frame": "tmltop.jpg"
    },
    "colors": {
      "frame": "#333333",
      "tab_background_text": "#666666"
    }
  },
  "version": "2.0",
  "name": "Simple Dark",
  "manifest_version": 2,
  "description": "designed for black royale type xp theme."
}