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## Complex rule condition schema clarifies nullable variant_id

The Catalog Products reference now marks `variant_id` as nullable in complex rule condition responses, matching what the API actually returns.

* **Nullable `variant_id`**: complex rules created through the v2 API or the control panel can return conditions without a `variant_id`, so the field may be `null` in `GET` and `PUT` responses.

For details, see the [Complex Rules reference](/developer/api-reference/rest/admin/catalog/products/complex-rules).