Examine source code of joke-extension

{
  "name": "Jokes",
  "description": "Enjoy a new joke with every click",
  "author": "Vaishnavi Konda",
  "version": "0.0.2",
  "manifest_version": 2,
  "browser_action": {
    "default_popup": "index.html",
    "default_icon": "logo.png"
  },
  "icons": {
    "400": "logo.png"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{9a34d8cd-5e98-4df4-9ef8-e1ab70411f44}"
    }
  }
}