This used to be a service that let you enter a domain name, and have returned a list of every machine-readable dataset hosted on that domain. With the closure of the organization that created and housed this service, so too this site had to be shuttered. (Access to Bing’s API, which powered this, is not free.)
However! You can install and run your own copy of LMGTDFY. The loss of this site is inconvenient, but thoroughly replaceable. If you want to stand up your own version of the site and make it public, let me know, and I’ll link to it here.