Domain Registration Info is Stored About the Pages
It’s been a long running conspiracy theory that Google’s status as a registrar feeds the algorithm. We can upgrade to a conspiracy fact. They store the latest registration information on a composite document level.
As previously discussed, this is likely used to inform sandboxing of new content. It may also be used to sandbox a previously registered domain that has changed ownership. I suspect the weight on this has been recently turned up with the introduction of the expired domain abuse spam policy.