Examine source code of Tab Manager

{
  "manifest_version": 2,
  "name": "Tab Manager",
  "version": "1.1",
  "description": "Manage your tabs with export and import functionality",
  "icons": {
    "48": "icons/icon-48.png"
  },
  "permissions": [
    "tabs",
    "downloads"
  ],
  "browser_action": {
    "default_icon": "icons/icon-48.png",
    "default_title": "Tab Manager",
    "default_popup": "popup/popup.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{42dd01a7-aedd-433a-8049-fb817f502312}"
    }
  }
}