ntp.tomsawyerlabs.com is a time server, not a website.
It serves time inside Tom Sawyer Labs' network only.

NTP:  ntp.tomsawyerlabs.com, UDP port 123
NTS:  ntp.tomsawyerlabs.com, key exchange on TCP port 4460

chrony:            server ntp.tomsawyerlabs.com iburst nts
systemd-timesyncd: NTP=ntp.tomsawyerlabs.com
Windows:           w32tm /config /manualpeerlist:ntp.tomsawyerlabs.com,0x8 /syncfromflags:manual /update