The Dbg widget controls the "verbosity" level.  Messages are
written  to  standard  output,  and  to  the  Debug  window,
depending on the level, which is a single-digit number.  You
can  modify  the  debug  level by clicking on the number and
typing a new value, or by using the Dbg menu to make  a  few
of the most useful changes to the level.  The levels are:

0 means produce no messages at all.

1 is the default, and gives error messages only.

2 and higher give more detail about details of the inner
  workings of the H viewer.

Note that, at level 2 and above, the  Help  (or  F1)  button
will  show  you  the  file pathnames that it is looking for.
This can be useful in filling in missing  help  information:
Set the debug level to 2 and press Help or F1 over a widget.
The help window will open and will have a list of the places
that  the  help routine looked for the information.  You can
cut out a path and paste it into an edit window  to  rapidly
create the help files.