/usr/share/gmt/cpt/dem2.cpt is in gmt-common 5.3.1+dfsg-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 | # $Id: dem2.cpt 16563 2016-06-18 04:09:08Z pwessel $
#
# Paul Wessel, modified from DEM_poster at cpt city to yield brown
#
#----------------------------------------------------------
# COLOR_MODEL = RGB
# RANGE = 0/4900
#----------------------------------------------------------
0 0/97/71 0.0102040816327 16/122/47
0.0102040816327 16/122/47 0.102040816327 232/215/125
0.102040816327 232/215/125 0.244897959184 161/67/0
0.244897959184 161/67/0 0.34693877551 100/50/25
0.34693877551 100/50/25 0.571428571429 110/109/108
0.571428571429 110/109/108 0.816326530612 255/254/253
0.816326530612 255/254/253 1 255/254/253
#----------------------------------------------------------
N gray
F white
B black
#----------------------------------------------------------
|