To see a description what the service is one has to run

curl -I https://runson.cloud/

"x-about: This site provides a query interface over the public IP address range manifests published by a number of the large cloud providers and CDNs. The /search path provides a simple boolean lookup (with region if possible) to determine if the passed IP (or the IPs a domain name resolves to) is present in a given provider's ranges, across all manifests. All other paths return the most specific logical blocks of the given provider's manifest that contain the IPs passed or resolved. It is run by github.com/sampointer <sam@outsidethe.net>"