Examine source code of Cookie Override

{
  "manifest_version": 2,
  "name": "Cookie Override",
  "version": "1.0",
  "description": "Allows to add rules overriding specific cookie values whenever a cookie is created or updated.",
  "icons": {
    "48": "icons/cookie-override-48.png",
    "96": "icons/cookie-override-96.png"
  },
  "permissions": [
    "tabs",
    "cookies",
    "storage",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background_scripts/background.js"
    ]
  },
  "options_ui": {
    "page": "options/options.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "cookie-override@rafbiels"
    }
  }
}