/usr/share/gnuplot/gnuplot/4.6/PostScript/ is in gnuplot-qt 4.6.4-2.
This file is owned by root:root, with mode 0o755.
..
/usr/share/gnuplot/gnuplot/4.6/PostScript/8859-1.ps
/usr/share/gnuplot/gnuplot/4.6/PostScript/8859-15.ps
/usr/share/gnuplot/gnuplot/4.6/PostScript/8859-2.ps
/usr/share/gnuplot/gnuplot/4.6/PostScript/8859-9.ps
/usr/share/gnuplot/gnuplot/4.6/PostScript/aglfn.txt
/usr/share/gnuplot/gnuplot/4.6/PostScript/cp1250.ps
/usr/share/gnuplot/gnuplot/4.6/PostScript/cp1251.ps
/usr/share/gnuplot/gnuplot/4.6/PostScript/cp437.ps
/usr/share/gnuplot/gnuplot/4.6/PostScript/cp850.ps
/usr/share/gnuplot/gnuplot/4.6/PostScript/cp852.ps
/usr/share/gnuplot/gnuplot/4.6/PostScript/koi8r.ps
/usr/share/gnuplot/gnuplot/4.6/PostScript/koi8u.ps
/usr/share/gnuplot/gnuplot/4.6/PostScript/prologue.ps
/usr/share/gnuplot/gnuplot/4.6/PostScript/utf-8.ps