Examine source code of Random Jokes Generator

{
  "manifest_version": 2,
  "name": "Random Joke Generator",
  "version": "1.0",
  "description": "Displays a random joke",
  "icons": {
    "48": "icon.png"
  },
  "browser_action": {
    "default_popup": "popup.html"
  },
  "permissions": [
    "<all_urls>"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{16dc533c-da80-4229-a076-2f0226449e3f}"
    }
  }
}