Download the contents of the given file. The response body is the raw file; the Content-Type is derived from the file extension and the original file name is returned in the Content-Disposition header. The required permission depends on the file's link type: person files require Read Files; business files require Limited Write Contributions or Full Write Accounting; batch files require Limited Read Contributions; bank_reconciliation files require Full Read Accounting; group files require being an administrator or member of the group; other link types follow the permissions of the record the file is attached to.