промежуточный выходной формат GNU roff (GNU roff intermediate output format)
Postprocessing
The roff postprocessors are programs that have the task to
translate the intermediate output into actions that are sent to a
device. A device can be some piece of hardware such as a
printer, or a software file format suitable for graphical or text
processing. The groff system provides powerful means that make
the programming of such postprocessors an easy task.
There is a library function that parses the intermediate output
and sends the information obtained to the device via methods of a
class with a common interface for each device. So a groff
postprocessor must only redefine the methods of this class. For
details, see the reference in section 'Files' below.
