Examine source code of Google Chat Popup

{
  "browser_action": {
    "browser_style": true,
    "default_title": "Google Chat",
    "default_icon": {
      "20": "icons/googlechat19.png",
      "40": "icons/googlechat38.png"
    }
  },
  "icons": {
    "50": "icons/googlechat.png",
    "100": "icons/googlechat@2x.png"
  },
  "description": "A simple Google Chat popup",
  "background": {
    "scripts": [
      "index.js"
    ]
  },
  "permissions": [
    "tabs"
  ],
  "manifest_version": 2,
  "name": "Google Chat Popup",
  "version": "1.0.5",
  "browser_specific_settings": {
    "gecko": {
      "id": "{9fd7927e-c184-4f3f-ba8e-9a905425fdf6}"
    }
  }
}