man.output.encoding — Encoding used for man-page output
This parameter specifies the encoding to use for files generated by the manpages stylesheet. Not all processors support specification of this parameter.
If the value of the man.charmap.enabled
  parameter is non-zero (the default), keeping the
  man.output.encoding parameter at its default
  value (UTF-8) or setting it to
  UTF-16 does not cause your
  man pages to be output in raw UTF-8 or UTF-16 -- because
  any Unicode characters for which matches are found in the enabled
  character map will be replaced with roff escape sequences before the
  final man-page files are generated.
So if you want to generate "real" UTF-8 man pages, without any
  character substitution being performed on your content, you need to
  set man.charmap.enabled to zero (which will
  completely disable character-map processing). 
You may also need to set
  man.charmap.enabled to zero if you want to
  output man pages in an encoding other than UTF-8
  or UTF-16. Character-map processing is based on
  Unicode character values and may not work with other output
  encodings.