Examine source code of Save Tabs Extension

{
  "manifest_version": 2,
  "name": "Save Tabs Extension",
  "version": "1.1.1",
  "description": "Save and restore current tabs",
  "permissions": [
    "tabs",
    "storage",
    "cookies",
    "identity"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "phan123123@gmail.com",
      "strict_min_version": "101.0"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_popup": "popup/popup.html"
  }
}