If you're testing locally or your server has an incorrect system time:

(await fetch("https://cdn.doubleverify.com/dvbm.js")).headers.get("date");

This works because https://cdn.doubleverify.com/dvbm.js returns both:

• access-control-allow-origin: *
• access-control-expose-headers: *

I'm using this specific URL since it shows up in your network logs on any page you load using StackOverflow.