/usr/share/tcltk/tcllib1.16/doctools2idx/ is in tcllib 1.16-dfsg-2.
This file is owned by root:root, with mode 0o755.
..
/usr/share/tcltk/tcllib1.16/doctools2idx/container.tcl
/usr/share/tcltk/tcllib1.16/doctools2idx/export.tcl
/usr/share/tcltk/tcllib1.16/doctools2idx/export_docidx.tcl
/usr/share/tcltk/tcllib1.16/doctools2idx/export_html.tcl
/usr/share/tcltk/tcllib1.16/doctools2idx/export_json.tcl
/usr/share/tcltk/tcllib1.16/doctools2idx/export_nroff.tcl
/usr/share/tcltk/tcllib1.16/doctools2idx/export_text.tcl
/usr/share/tcltk/tcllib1.16/doctools2idx/export_wiki.tcl
/usr/share/tcltk/tcllib1.16/doctools2idx/import.tcl
/usr/share/tcltk/tcllib1.16/doctools2idx/import_docidx.tcl
/usr/share/tcltk/tcllib1.16/doctools2idx/import_json.tcl
/usr/share/tcltk/tcllib1.16/doctools2idx/msgcat_c.tcl
/usr/share/tcltk/tcllib1.16/doctools2idx/msgcat_de.tcl
/usr/share/tcltk/tcllib1.16/doctools2idx/msgcat_en.tcl
/usr/share/tcltk/tcllib1.16/doctools2idx/msgcat_fr.tcl
/usr/share/tcltk/tcllib1.16/doctools2idx/parse.tcl
/usr/share/tcltk/tcllib1.16/doctools2idx/pkgIndex.tcl
/usr/share/tcltk/tcllib1.16/doctools2idx/structure.tcl