Examine source code of Save Tabs to Text

{
  "manifest_version": 2,
  "name": "Save Tabs to Text",
  "version": "2.0",
  "description": "Save tabs to a text file.",
  "browser_specific_settings": {
    "gecko": {
      "id": "tabtxt@cowtools.net"
    }
  },
  "icons": {
    "48": "icons/icon48.png"
  },
  "permissions": [
    "tabs",
    "storage",
    "downloads",
    "clipboardWrite"
  ],
  "browser_action": {
    "default_icon": "icons/icon32.png",
    "default_title": "Save Tabs",
    "default_popup": "save_dialog.html"
  },
  "background": {
    "scripts": [
      "tabtxt.js"
    ],
    "persistent": false
  }
}