FM / ColorSpace

/usr/share/ghostscript/9.55.0/Resource/ColorSpace/

/usr/share/ghostscript/9.55.0/Resource/ColorSpace

Name	Size	Mode	Actions
DefaultCMYK	1241	0644	edit dl rm
DefaultGray	925	0644	edit dl rm
DefaultRGB	1009	0644	edit dl rm
sGray	1128	0644	edit dl rm
sRGB	1133	0644	edit dl rm
TrivialCMYK	1237	0644	edit dl rm

Edit: /usr/share/ghostscript/9.55.0/Resource/ColorSpace/sGray (1128B)

% Copyright (C) 2001-2021 Artifex Software, Inc.
% All Rights Reserved.
%
% This software is provided AS-IS with no warranty, either express or
% implied.
%
% This software is distributed under license and may not be copied,
% modified or distributed except as expressly authorized under the terms
% of the license contained in the file LICENSE in this distribution.
%
% Refer to licensing information at http://www.artifex.com or contact
% Artifex Software, Inc.,  1305 Grant Avenue - Suite 200, Novato,
% CA 94945, U.S.A., +1(415)492-9861, for further information.
%

% One-component color space similar to sRGB color space.

currentglobal true setglobal

/sGray
[ /CIEBasedA
  3 dict begin
    /WhitePoint [ 0.9505 1 1.0890 ] def % D65

/DecodeLMN [  % sRGB gamma transform 
      { dup 0.03928 le { 12.92321 div } { 0.055 add 1.055 div 2.4 exp } ifelse }
      bind dup dup ] def

/MatrixLMN [ % sRGB to XYZ (D65) matrix (ITU-R BT.709-2 Primaries)
      0.412457 0.212673 0.019334
      0.357576 0.715152 0.119192
      0.180437 0.072175 0.950301 ] def
  currentdict end
] 
/ColorSpace defineresource pop

setglobal

cmd: