Item custom fields contain custom fields defined under item table in your Chargebee site
Note:
If you create a custom field for items in Chargebee (for example, cf_age), it will appear as a column with the same name (cf_age) in this table. This helps you include your own business-specific details in reports and data analysis.
Each row is uniquely identified by this combination. Use these columns together as the upsert key when applying incremental datasets to your warehouse.