Examine source code of Save Tab Session

{
  "manifest_version": 2,
  "name": "Save Tab Session",
  "version": "1.0",
  "description": "Save your open tabs for later sessions.",
  "permissions": [
    "tabs",
    "storage"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "48": "icon.png"
    }
  },
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{afb6a058-d7e8-4069-819f-3827214f2ea3}"
    }
  }
}