All \[charXXX] special character names have been removed from the font
files.  They don't make sense for Unicode.

The following special character name from the AT&T troff manual by
Ossanna and Kernighan is unmapped:

  bs    shaded solid ball (Bell System logo, AT&T logo)

Code point 0x002D has not been given a name because its Unicode name
HYPHEN-MINUS is so ambiguous that it is unusable for serious typographic
work.

\[wp] has been mapped to 0x2118, because according to Unicode 4.1's
NamesList.txt, U+2118 SCRIPT CAPITAL P is really a Weierstrass 'p',
neither SCRIPT nor CAPITAL.

The following line could be added; \[space] is known to devps but is not
documented and not known to devdvi (actually, there is no space glyph
within the TeX system).

  space   24   0   0x0020

devps maps \[*U] to 'Upsilon1', which is equivalent to 0x03D2.  We map
it to 0x03A5 instead.

devps maps \[*W] to 'Omega', which is equivalent to either 0x2126 or
0x03A9.  We map it to 0x03A9.

devps maps \[*D] to 'Delta', which is equivalent to either 0x2206 or
0x0394.  We map it to 0x0394.


Adding Unicode characters
-------------------------

Assume you want to use a Unicode character not provided in the list, say
U+20AC.  You need to do two things:

- Add a line

    u20AC   24   0   0x20AC

  (the second column is computed as 24 * wcwidth(0x20AC)) to the file
  R.proto, or, when groff is already installed, to the four font
  description files in $(prefix)/share/groff/<version>/font/devutf8/.

- In your source file, use the notation \[u20AC] to access it.