Examine source code of cool forest

{
  "theme": {
    "images": {
      "theme_frame": "darkforestinvertcool.jpg"
    },
    "colors": {
      "frame": "#3462ed",
      "tab_background_text": "#f7f2f2"
    }
  },
  "version": "2.0",
  "name": "cool forest",
  "manifest_version": 2,
  "description": "a blue forest"
}