This note is in Hasura.GraphQL.Execute.Subscription.Poll.Common. It is referenced at:
We only want to log the minimal information in the livequery-poller-log as it could be expensive to log the details of every subscriber (all poller related information can always be retrieved by dumping the current live queries state) We capture a lot more details in PollDetails and BatchExecutionDetails than that is logged currently as other implementations such as pro can use them if they need to.