/usr/share/texlive/texmf-dist/tex/plain/graphics-pln/graphicx.tex is in texlive-plain-extra 2014.20141024-1.
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1 2 3 4 5 6 7 8 9 10 11 | % Plain TeX interface to graphicx package.
% David Carlisle
\input miniltx
\def\Gin@driver{dvips.def}
\input graphicx.sty
\resetatcatcode
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