Output styles available:
name description
list display a full list of all violations, with preview of the current item (large dialog)
simple a small & simple dialog that navigates the user through the violations one by one, sequentially
print print the list to stdout in human readable form
log print the list as INFO lines in the log in human readable form
dump print the list to stdout in script readable form

Note that the design rule check uses the current board rule settings, not the current style settings.