Odata attributes required for file download operations

If you mean an OEM property that would be a pointer/link to a non-Redfish resource, then no, that wouldn't be an @odata.id because the target resource won't behave like the spec would mandate. So no @odata.id or @odata.type required.

We have several places in the standard schema like this - for example, in the Assembly schema, the raw assembly data can be downloaded using the URI value of `BinaryDataURI`. We always name those properties with the "URI" suffix to help folks understand those. Basically any URI property that cannot be guaranteed to be a Redfish resource, and therefore isn't guaranteed to follow the Redfish Specification, falls into that category.

Now, if the resource is a JSON document, it would be best to make that align to the Redfish data model with an OEM schema... But it's not required.

Jeff