Examine source code of JS Error Notifier

{
  "manifest_version": 2,
  "name": "JS Error Notifier",
  "version": "1.0",
  "description": "Display JS errors in a browser popup.",
  "permissions": [
    "activeTab"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{d47d4f74-557b-4239-a599-d65808631dc9}"
    }
  }
}