Examine source code of Easy Clear History

{
  "manifest_version": 2,
  "name": "Easy Clear History",
  "version": "1.0",
  "description": "One button to clean browsing history.",
  "permissions": [
    "browsingData"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png"
  },
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{b3caa519-ad89-4da7-8e43-2fd9c5c4046e}"
    }
  }
}