Newsreader extensions are those which are primarily used by
    newsreading clients. Following are the descriptions of each
    newsreader extension commands and the responses which will
    be returned by those commands.

    Each command is shown in upper case for clarity, although
    case is ignored in the interpretation of commands by the
    NNTP server.  Any parameters are shown in lower case.  A
    parameter shown in [square brackets] is optional.  For
    example, [GMT] indicates that the triglyph GMT may present
    or omitted. A parameter that may be repeated is followed
    by an ellipsis. Mutually exclusive parameters are separated
    by a vertical bar (|) character. For example, ggg|<message-id>
    indicates that  a group name or a <message-id> may be
    specified, but not both. Some parameters, notably <message-id>,
    is case specific. See RFC 1036 for these details.

    Also, certain commands make use of a pattern for selection
    of multiple news groups. The pattern in all cases is based
    on the wildmat[4] format introduced by Rich Salz in 1986.
    Arguments expected to be in wildmat format will be
    represented by the string wildmat. This format is discussed
    in detail in section 3.3 of this document.