/sys$common/syshlp/helplib.hlb VIEW, Qualifiers, /FORMAT  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /FORMAT=fmt-name
       /FORMAT=DDIF (default)

    Specifies the format of your input file. The input formats that
    you can use with the CDA Viewer depend on the CDA converters
    installed on your system. The default input format is DDIF. Input
    formats supported by converters installed with the DEC CDA Base
    Services for DECwindows Motif for OpenVMS and their default file
    extensions are as follows:

    Input Format   File Extension

    DDIF           .DDIF
    DTIF           .DTIF
    TEXT           .TXT

    Compaq's CDA Converter Library provides additional converters
    that support display of other popular file formats. If you have
    the CDA Converter Library Version 2.2 or later installed on your
    system, see HELP CDA_Converters for more information, or contact
    your system manager for a complete list of input converters
    available on your system.