Examine source code of latest-download-delete

{
  "description": "Shows the last downloaded item, and lets you open or delete it",
  "manifest_version": 2,
  "name": "latest-download-delete",
  "version": "1.1resigned1",
  "homepage_url": "https://github.com/nabendu82/latest-download-delete",
  "icons": {
    "32": "icons/logo_32.png",
    "48": "icons/logo_48.png",
    "64": "icons/logo_64.png"
  },
  "permissions": [
    "downloads",
    "downloads.open"
  ],
  "browser_action": {
    "browser_style": true,
    "default_icon": "icons/logo_64.png",
    "default_title": "Download Delete",
    "default_popup": "popup/latest_download.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{80b4a3ee-3c7c-4807-8768-5ce7dcf49573}"
    }
  }
}