We use custom email properties to tag and organize our marketing emails. However, there is currently no way to retrieve the values of these properties through the API.
The `GET /marketing/v3/emails` and `GET /marketing/v3/emails/{emailId}` endpoints do not return custom property values, and the `includedProperties` parameter does not work for them either. The `GET /crm/v3/properties/marketing_emails` endpoint returns property definitions only, not the values.
This creates a gap for teams that use custom email properties for reporting, segmentation, or integration with external tools, as there is no programmatic way to access this data.
Please expose custom email property values in the Marketing Email API response, consistent with how custom properties are handled for other CRM objects.