Examine source code of Summarize the Internet

{
  "manifest_version": 2,
  "name": "Summarize the Internet",
  "version": "1.9.0",
  "description": "Displays a summary of the text or article on the current page.",
  "author": "Patrick Dhondt",
  "developer": {
    "name": "Patrick Dhondt",
    "url": "https://artistdetective.wordpress.com"
  },
  "permissions": [
    "activeTab"
  ],
  "icons": {
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "browser_action": {
    "browser_style": true,
    "default_icon": "icons/icon32.png",
    "default_title": "Summarize page",
    "default_popup": "summarise.htm"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{9df93558-80fc-4231-96fd-ad26f29bef3c}"
    }
  }
}