We've recently added two additional dimensions to our AppNexus connector!
Split ID and Split Name are now available for all report types and to get historical data for these dimensions, you have to reach out to support@funnel.io to request a backfill of the data.
For more information, please read What data can I get from AppNexus? If you have any other questions, you are more than welcome to email or write to us in the in-app chat.