package.json declares a preinstall hook ("preinstall": "node index.js") that auto-executes on npm install. index.js issues an HTTP GET to the hardcoded bare IP 10.107.121.85:8000 at path /ping_472839_ctf. The unique token in the URL path makes the request itself the exfiltrated signal — it confirms to the operator of that endpoint that the package executed inside the installer's environment, leaking the installer's source IP and the fact that code execution succeeded. The package advertises no functionality that would justify a phone-home, and the destination is a private-range IP rather than any documented service. This is the canonical dependency-confusion / CTF probe shape, and the same mechanism would deliver any payload an attacker placed in index.js.