Examine source code of Colorful Windows

{
  "manifest_version": 2,
  "name": "Colorful Windows",
  "version": "4.0",
  "description": "Dynamic colorful firefox windows",
  "homepage_url": "https://github.com/DaveDuck321/Colorful-window-theme",
  "icons": {
    "128": "icon.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "tabs",
    "theme",
    "storage"
  ],
  "browser_action": {
    "default_title": "Pick Window Color",
    "default_popup": "popup.html",
    "default_icon": {
      "128": "icon.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{ca685ec4-9ad3-4523-9bbc-db687d34b461}"
    }
  }
}