The country file can be copied into the $HOME/.xdx directory and Xdx
will load it automatically or placed in another directory and the ‘-c’
or ‘–cty_dat’ command line options are used or the ‘XDX_CTY’
environment variable is set.
Instructions are available from the Help|Manual menu or pressing Ctl-H in the main window. The manual also includes URIs for downloading updated cty.dat.