Examine source code of simple cloud

{
  "theme": {
    "images": {
      "theme_frame": "header_firefox.jpg"
    },
    "colors": {
      "frame": "#074068",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "simple cloud",
  "manifest_version": 2,
  "description": "Just part of a simple cloud on a grayish sky. I wanted something that simple that I would want to see it every day."
}