I wonder what else they're serving up from my domains using my name?

I often use cdn-cgi/trace endpoints to do latency measurements, sync time, geo-locate; real handy.

Wow very cool

I wonder what's the 'sliver' property

It's information that's only really useful to us. It refers to a set of machines running the same version of our software. Part of how we do progressive rollouts of software.

Thanks for answering!

Wow that's terrible. Is this written anywhere in their terms that you agree to let them host arbitrary content under your own domain without your knowledge?