Identifies the name of the X display to which you are authorizing
    access. The display name follows the supported display name
    format:

    [transport/]host:[:]server[.screen]

    This format enables you to use a single X authority file to
    grant varying levels of access to different X display servers
    and connection families.

    For example, the following entries grant access to the local
    display server on node HUBBUB and the remote display server on
    node ZEPHYR via the DECnet transport:

 local/HUBBUB:0 MIT-MAGIC-COOKIE-1 cfcc5ef98f9718f90154f355c0ae9f62
 decnet/ZEPHYR::0 MIT-MAGIC-COOKIE-1 cfcc5ef98f9718f90154f355c0ae9f62

    o  [transport/]
       Identifies the network transport used to connect to an X
       display server. See the DECwindows Motif documentation for
       a list of the supported transport values. If a transport value
       is not specified, the default value is interpreted from the
       format of the remaining portions of the display-name entry,
       for example:

          Host address and one colon (116.94.24.187:0) (TCP/IP)
          Two colons (::0 or ZEPHYR::0) (DECnet)
          No host name or address and one colon (:0) (local)

    o  host[:]
       Identifies the name of the host system where the X display
       server is located. A value of 0 is interpreted as the local
       host, which is the default. The type of host is determined
       by the transport value. See the DECwindows documentation for
       examples of valid host name and address formats.

    o  :server
       Identifies the server. This value is required and must be
       preceded by a single colon (:). Typically the value for a
       single-server system is :0. If you are specifying a display
       on a multi-server system (such as when using a proxy server),
       additional values may apply depending on the number of servers
       in the configuration. If you have specified a display device
       (with the SET DISPLAY command), the server portion of the
       entry is assumed from the device specification.

    o  [.screen]
       Identifies the screen. On OpenVMS Alpha and OpenVMS I64
       systems, the screen value is not held in the X authority file
       and is ignored when included in a command. All screens on a
       single server have the same authorization.