cds.import is available in the CDS development tool kit version 4.3.1 onwards .
This option is only applicable for OData conversion. It accepts a list of namespaces whose attributes are to be retained in the CSN / CDS file. To include all the namespaces present in the EDMX pass "*".
For OData V2 EDMX attributes with the namespace "sap" & "m" are captured by default.