Examine source code of FreshDownload

{
  "description": "Shows the last downloaded item, and lets you open or delete it",
  "manifest_version": 2,
  "name": "FreshDownload",
  "version": "1.1resigned1",
  "permissions": [
    "downloads",
    "downloads.open"
  ],
  "browser_action": {
    "browser_style": true,
    "default_title": "FreshDownload",
    "default_popup": "popup/fresh.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{e3586b42-4665-45eb-aac2-4000d81818c4}"
    }
  }
}