/usr/share/common-lisp/source/ is in cl-plplot 0.6.0-4.
This file is owned by root:root, with mode 0o755.
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/usr/share/common-lisp/source/cl-plplot/
/usr/share/common-lisp/source/cl-plplot/cl-plplot.asd
/usr/share/common-lisp/source/cl-plplot/src/
/usr/share/common-lisp/source/cl-plplot/src/system/
/usr/share/common-lisp/source/cl-plplot/src/system/api.lisp
/usr/share/common-lisp/source/cl-plplot/src/system/defcfun.lisp
/usr/share/common-lisp/source/cl-plplot/src/system/loadlib.lisp
/usr/share/common-lisp/source/cl-plplot/src/system/misc.lisp
/usr/share/common-lisp/source/cl-plplot/src/window/
/usr/share/common-lisp/source/cl-plplot/src/window/3D-mesh.lisp
/usr/share/common-lisp/source/cl-plplot/src/window/3D-window.lisp
/usr/share/common-lisp/source/cl-plplot/src/window/axis-label.lisp
/usr/share/common-lisp/source/cl-plplot/src/window/axis.lisp
/usr/share/common-lisp/source/cl-plplot/src/window/bar-graph.lisp
/usr/share/common-lisp/source/cl-plplot/src/window/classes.lisp
/usr/share/common-lisp/source/cl-plplot/src/window/color-table.lisp
/usr/share/common-lisp/source/cl-plplot/src/window/contour-plot.lisp
/usr/share/common-lisp/source/cl-plplot/src/window/extended-color-table.lisp
/usr/share/common-lisp/source/cl-plplot/src/window/macros.lisp
/usr/share/common-lisp/source/cl-plplot/src/window/package.lisp
/usr/share/common-lisp/source/cl-plplot/src/window/plot.lisp
/usr/share/common-lisp/source/cl-plplot/src/window/surface-plot.lisp
/usr/share/common-lisp/source/cl-plplot/src/window/text-item.lisp
/usr/share/common-lisp/source/cl-plplot/src/window/text-label.lisp
/usr/share/common-lisp/source/cl-plplot/src/window/utility-functions.lisp
/usr/share/common-lisp/source/cl-plplot/src/window/window.lisp
/usr/share/common-lisp/source/cl-plplot/src/window/x-y-plot.lisp