Examine source code of Session Saver Extension

{
  "manifest_version": 3,
  "name": "Session Saver",
  "version": "1.1",
  "description": "Save and restore multiple tab sessions, choosing which URLs to include.",
  "permissions": [
    "tabs",
    "storage"
  ],
  "action": {
    "default_popup": "popup/popup.html",
    "default_icon": {
      "16": "icons/icon16.png",
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
    }
  },
  "options_page": "options/options.html",
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "aaossa.dev@gmail.com"
    }
  }
}