What is the host "xp.apple.com" for and what is sent there? Ever since I have installed a Pi-hole DNS/DHCP server at my home, I see the host xp.apple.com pop up as one of the most blocked hosts. The amount of lookups attempted is ridiculous, at around 10% of all DNS lookups combined, even eclipsing graph.facebook.com, which is usually the worst offender.

Hence my question: what is xp.apple.com for and what kind of data is sent there. I am aware of Apple's server connection information but there's no mention of what kind of data is transferred. Also, several internet searches did not bring any more info about it to light.
It seems to be related to the app store and os updates. All my apple devices attempt to connect to it during updates. On MacOS the processes which attempt connection are commerce, appstoreagent, rtcreportingd and App Store.

I would speculate that it is for some kind of telemetry, as I have had it blocked for a couple of months now and it has never caused any updates to fail. I suspect the same is true for configuration.apple.com .