Changes to Download extension

added the optional property linkToDocs to the response with the 400 status

added the optional property linkToDocs to the response with the 404 status

added the optional property linkToDocs to the response with the 500 status

the response property context/items/params became required for the status 400

the response property context/items/params became required for the status 404

the response property context/items/params became required for the status 500

endpoint added