Displays the XBoard documentation in info format. For this feature to
work, you must have the GNU info program installed on your system, and
the file xboard.info must either be present in the current
working directory, or have been installed by the ‘make install’
command when you built XBoard.
Man XBoard
Displays the XBoard documentation in man page format. For this
feature to work, the file xboard.6 must have been installed by
the ‘make install’ command when you built XBoard, and the
directory it was placed in must be on the search path for your
system's ‘man’ command.
Hint
Displays a move hint from the chess engine.
Book
Displays a list of possible moves from the chess engine's opening
book. The exact format depends on what chess engine you are using.
With GNU Chess 4, the first column gives moves, the second column
gives one possible response for each move, and the third column shows
the number of lines in the book that include the move from the first
column. If you select this option and nothing happens, the chess
engine is out of its book or does not support this feature.