.onion, aka a TOR internal URL. They look like this.

vaylian 15 hours ago | parent | next [-]

There are also many web sites that provide an onion address in addition to their clearnet address. For example, the BBC: https://www.bbc.com/news/technology-50150981

bombcar 7 hours ago | parent | prev | next [-]

If I ever get a .onion (everyone should have an onion probably) I'll also register the same domain "dot net, it's dot com" just for the lols.

And onion urls are a sha hash of i think the private key of the site

	▲	gzread 8 hours ago \| parent [-]
		They contain the full key now which is why they are longer. Apparently it was necessary to fix the vulnerabilities in the previous version. Public key obviously, not private.