/usr/share/tcltk/tcl8.6/vtk/ is in tcl-vtk 5.8.0-14.1ubuntu3.
This file is owned by root:root, with mode 0o755.
..
/usr/share/tcltk/tcl8.6/vtk/FindString.tcl
/usr/share/tcltk/tcl8.6/vtk/PrintSelfCheck.tcl
/usr/share/tcltk/tcl8.6/vtk/TestSetGet.tcl
/usr/share/tcltk/tcl8.6/vtk/prtImageTest.tcl
/usr/share/tcltk/tcl8.6/vtk/rtImageTest.tcl
/usr/share/tcltk/tcl8.6/vtk/vtkinteraction/
/usr/share/tcltk/tcl8.6/vtk/vtkinteraction/CMakeLists.txt
/usr/share/tcltk/tcl8.6/vtk/vtkinteraction/Interactor.tcl
/usr/share/tcltk/tcl8.6/vtk/vtkinteraction/bindings-iw.tcl
/usr/share/tcltk/tcl8.6/vtk/vtkinteraction/bindings-rw.tcl
/usr/share/tcltk/tcl8.6/vtk/vtkinteraction/bindings.tcl
/usr/share/tcltk/tcl8.6/vtk/vtkinteraction/setget.tcl
/usr/share/tcltk/tcl8.6/vtk/vtkinteraction/vtkinteraction.tcl.in