Examine source code of Save Page as HTML its

{
  "manifest_version": 2,
  "name": "Save Page as HTML",
  "version": "1.0",
  "description": "Save the current page as a single HTML file.",
  "permissions": [
    "activeTab"
  ],
  "browser_action": {
    "default_title": "Save Page",
    "default_icon": "icon.png",
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{830e996c-457d-4750-89e1-6b509ff12bbe}"
    }
  }
}