/usr/share/doc/libplplot11/examples/lua/ is in libplplot-dev 5.9.9-2ubuntu2.
This file is owned by root:root, with mode 0o755.
..
/usr/share/doc/libplplot11/examples/lua/CMakeLists.txt
/usr/share/doc/libplplot11/examples/lua/plplot_examples.lua
/usr/share/doc/libplplot11/examples/lua/x01.lua
/usr/share/doc/libplplot11/examples/lua/x02.lua
/usr/share/doc/libplplot11/examples/lua/x03.lua
/usr/share/doc/libplplot11/examples/lua/x04.lua
/usr/share/doc/libplplot11/examples/lua/x05.lua
/usr/share/doc/libplplot11/examples/lua/x06.lua
/usr/share/doc/libplplot11/examples/lua/x07.lua
/usr/share/doc/libplplot11/examples/lua/x08.lua
/usr/share/doc/libplplot11/examples/lua/x09.lua
/usr/share/doc/libplplot11/examples/lua/x10.lua
/usr/share/doc/libplplot11/examples/lua/x11.lua
/usr/share/doc/libplplot11/examples/lua/x12.lua
/usr/share/doc/libplplot11/examples/lua/x13.lua
/usr/share/doc/libplplot11/examples/lua/x14.lua
/usr/share/doc/libplplot11/examples/lua/x15.lua
/usr/share/doc/libplplot11/examples/lua/x16.lua
/usr/share/doc/libplplot11/examples/lua/x17.lua
/usr/share/doc/libplplot11/examples/lua/x18.lua
/usr/share/doc/libplplot11/examples/lua/x19.lua
/usr/share/doc/libplplot11/examples/lua/x20.lua
/usr/share/doc/libplplot11/examples/lua/x21.lua
/usr/share/doc/libplplot11/examples/lua/x22.lua
/usr/share/doc/libplplot11/examples/lua/x23.lua
/usr/share/doc/libplplot11/examples/lua/x24.lua
/usr/share/doc/libplplot11/examples/lua/x25.lua
/usr/share/doc/libplplot11/examples/lua/x26.lua
/usr/share/doc/libplplot11/examples/lua/x27.lua
/usr/share/doc/libplplot11/examples/lua/x28.lua
/usr/share/doc/libplplot11/examples/lua/x29.lua
/usr/share/doc/libplplot11/examples/lua/x30.lua
/usr/share/doc/libplplot11/examples/lua/x31.lua
/usr/share/doc/libplplot11/examples/lua/x33.lua