/usr/share/plplot5.10.0/tcl/cmap1a.pal is in plplot-tcl 5.10.0+dfsg-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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4 #5500ff 00 #010005 44 #050000 55 #ff0000 100