/usr/lib/ruby/vendor_ruby/ is in ruby-tioga 1.19.1-2.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/Dobjects/
/usr/lib/ruby/vendor_ruby/Dobjects/Dtable_extras.rb
/usr/lib/ruby/vendor_ruby/Dobjects/Dvector_extras.rb
/usr/lib/ruby/vendor_ruby/Dobjects/Function_extras.rb
/usr/lib/ruby/vendor_ruby/Dobjects/Numeric_extras.rb
/usr/lib/ruby/vendor_ruby/Tioga/
/usr/lib/ruby/vendor_ruby/Tioga/Arcs_and_Circles.rb
/usr/lib/ruby/vendor_ruby/Tioga/ColorConstants.rb
/usr/lib/ruby/vendor_ruby/Tioga/Colorbars.rb
/usr/lib/ruby/vendor_ruby/Tioga/Colormaps.rb
/usr/lib/ruby/vendor_ruby/Tioga/Coordinate_Conversions.rb
/usr/lib/ruby/vendor_ruby/Tioga/Creating_Paths.rb
/usr/lib/ruby/vendor_ruby/Tioga/Doc.rb
/usr/lib/ruby/vendor_ruby/Tioga/Executive.rb
/usr/lib/ruby/vendor_ruby/Tioga/FigMkr.rb
/usr/lib/ruby/vendor_ruby/Tioga/FigureConstants.rb
/usr/lib/ruby/vendor_ruby/Tioga/Figures_and_Plots.rb
/usr/lib/ruby/vendor_ruby/Tioga/Images.rb
/usr/lib/ruby/vendor_ruby/Tioga/Legends.rb
/usr/lib/ruby/vendor_ruby/Tioga/MarkerConstants.rb
/usr/lib/ruby/vendor_ruby/Tioga/Markers.rb
/usr/lib/ruby/vendor_ruby/Tioga/Page_Frame_Bounds.rb
/usr/lib/ruby/vendor_ruby/Tioga/Rectangles.rb
/usr/lib/ruby/vendor_ruby/Tioga/Shading.rb
/usr/lib/ruby/vendor_ruby/Tioga/Special_Paths.rb
/usr/lib/ruby/vendor_ruby/Tioga/Strokes.rb
/usr/lib/ruby/vendor_ruby/Tioga/TeX_Text.rb
/usr/lib/ruby/vendor_ruby/Tioga/Titles_and_Labels.rb
/usr/lib/ruby/vendor_ruby/Tioga/Transparency.rb
/usr/lib/ruby/vendor_ruby/Tioga/Using_Paths.rb
/usr/lib/ruby/vendor_ruby/Tioga/Utils.rb
/usr/lib/ruby/vendor_ruby/Tioga/X_and_Y_Axes.rb
/usr/lib/ruby/vendor_ruby/Tioga/irb_tioga.rb
/usr/lib/ruby/vendor_ruby/Tioga/tioga.rb
/usr/lib/ruby/vendor_ruby/Tioga/tioga_ui.rb
/usr/lib/ruby/vendor_ruby/Tioga/tioga_ui_cmds.rb
/usr/lib/ruby/vendor_ruby/Tioga/maker.rb
/usr/lib/ruby/vendor_ruby/Tioga/TexPreamble.rb