Examine source code of Window Autosaver

{
  "manifest_version": 3,
  "name": "Window Saver",
  "version": "1.4",
  "description": "Autosave all tabs when you close a window",
  "icons": {
    "128": "logo.png"
  },
  "permissions": [
    "storage",
    "tabs"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "main.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "gayali.rohit@gmail.com"
    }
  },
  "action": {
    "default_icon": {
      "128": "logo.png"
    },
    "default_popup": "popup.html",
    "default_title": "Open saved windows"
  }
}