Examine source code of URL Shortener

{
  "manifest_version": 2,
  "name": "URL Shortener",
  "version": "1.0",
  "description": "Shorten URLs quickly with is.gd and copy them to your clipboard",
  "permissions": [
    "activeTab",
    "clipboardWrite",
    "https://is.gd/*"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "URL Shortener"
  },
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{7f5807f0-a129-4473-8bfa-acf571161eab}"
    }
  }
}