http://k3oxb4lrs7l3vt2lhy3w5ilrrqzeltdxjyne3t7sctmnyu3ypwpuszid.onion/sni-bug.html
In some countries, ISPs allow customers to access certain SNIs for free. These are called "zero-rated" hosts. If the server at the IP address pointed to by the SNI is willing to forward the client's traffic to a second server, then the first server is called an "SNI bug host."