Examine source code of ddns

{
  "manifest_version": 2,
  "name": "ddns",
  "version": "1.1resigned1",
  "description": "Send ip updates to various ddns services.",
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png"
  },
  "background": {
    "scripts": [
      "ddns.js"
    ]
  },
  "permissions": [
    "https://dynupdate.no-ip.com/nic/update",
    "https://*.dynv6.com/api/update",
    "*://*.dyn.dns.he.net/nic/update",
    "storage",
    "webRequest",
    "webRequestBlocking"
  ],
  "options_ui": {
    "page": "options.html",
    "browser_style": true
  },
  "applications": {
    "gecko": {
      "id": "extension@various.ddns"
    }
  }
}