Examine source code of History Shortcut

{
  "manifest_version": 2,
  "name": "History Shortcut",
  "version": "1.0",
  "description": "Quick access to recently visited pages and study-related sites.",
  "permissions": [
    "history"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png"
  },
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{4472acc6-d6a9-427d-860b-5890c2ad6980}"
    }
  }
}