/usr/share/gmt/cpt/gray.cpt is in gmt-common 5.3.1+dfsg-2.
This file is owned by root:root, with mode 0o644.
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1 2 3 4 5 6 7 8 | # $Id: gray.cpt 16562 2016-06-18 04:04:08Z pwessel $
#
# Plain linear gray color table
#----------------------------------------------------------
# COLOR_MODEL = RGB
#----------------------------------------------------------
0 black 1 white
#----------------------------------------------------------
|