An https URL. I assume this is some sort of joke.
If it does lead to an HTTPS page, I believe that only happens when your browser tries HTTPS before HTTP (if it tries HTTP at all).
The irony has not gone unnoticed: https://twitter.com/NeverSSL/status/1456310362551164928
> 1. Why does neverssl.com use Javascript to redirect to a random subdomain?
> Over the last year users reported that some networks aggressively cache the fake DNS and pages they use for wifi capture. Neverssl.com now works around this generating a request to a random subdomain - this will bust any DNS cache, and any HTTP cache. It also means that if your browser or ISP caches the Neverssl.com page itself, that's fine.
> the domain isn't intended to be a general purpose endpoint for things like availability testing so we do not encourage that kind of usage