Examine source code of Text Summary Tool

{
  "manifest_version": 2,
  "name": "Summarize Text",
  "version": "1.0",
  "description": "Summarizes selected text.",
  "permissions": [
    "activeTab",
    "contextMenus"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "48": "icon.png"
    }
  },
  "icons": {
    "48": "icon.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{9c039752-0510-48af-9aa4-db3606167ed5}"
    }
  }
}