Examine source code of grey rainbow

{
  "theme": {
    "images": {
      "theme_frame": "header_2.jpg"
    },
    "colors": {
      "frame": "#666666",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "grey rainbow",
  "manifest_version": 2,
  "description": "color bands across a medium grey background."
}