To prevent normalization information for a specific hardware model from being sent to the ServiceNow Content Service, you need to select the Exclude from content service check box on the Normalization tab of the hardware model record1.
The ServiceNow Content Service is a cloud-based service that provides normalized data for hardware and consumable models. It helps you to keep your model data consistent and up to date2.
The other options are not valid ways to exclude a hardware model from the content service. There is no Exclude or Opt-out button on the hardware model record. There is also no Opt-out from content service check box on the Normalization tab of the hardware model record. Reference: 1: Work with hardware normalization 2: ServiceNow Content Service