VMS Help COPY, /FTP, Qualifiers, /FDL  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    This qualifier is optional. Causes interaction with an FDL (file
    definition language) file. If the file is being copied to the
    local OpenVMS system, a remote FDL file is sought and interpreted
    for the operation. If the file is being copied outside the local
    OpenVMS system, an FDL file is generated and copied in addition
    to the requested file. If the /FDL qualifier is specified and the
    vendor application does not support it, a warning message may be
    issued.