/usr/lib/ruby/vendor_ruby/ is in ruby-spreadsheet 0.6.5.7-1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/spreadsheet/
/usr/lib/ruby/vendor_ruby/spreadsheet/excel/
/usr/lib/ruby/vendor_ruby/spreadsheet/excel/reader/
/usr/lib/ruby/vendor_ruby/spreadsheet/excel/reader/biff8.rb
/usr/lib/ruby/vendor_ruby/spreadsheet/excel/reader/biff5.rb
/usr/lib/ruby/vendor_ruby/spreadsheet/excel/internals.rb
/usr/lib/ruby/vendor_ruby/spreadsheet/excel/row.rb
/usr/lib/ruby/vendor_ruby/spreadsheet/datatypes.rb
/usr/lib/ruby/vendor_ruby/spreadsheet/excel/worksheet.rb
/usr/lib/ruby/vendor_ruby/spreadsheet/excel/offset.rb
/usr/lib/ruby/vendor_ruby/spreadsheet/excel/workbook.rb
/usr/lib/ruby/vendor_ruby/spreadsheet/excel/writer.rb
/usr/lib/ruby/vendor_ruby/spreadsheet/excel/error.rb
/usr/lib/ruby/vendor_ruby/spreadsheet/excel/sst_entry.rb
/usr/lib/ruby/vendor_ruby/spreadsheet/excel/internals/
/usr/lib/ruby/vendor_ruby/spreadsheet/excel/internals/biff8.rb
/usr/lib/ruby/vendor_ruby/spreadsheet/excel/internals/biff5.rb
/usr/lib/ruby/vendor_ruby/spreadsheet/excel/reader.rb
/usr/lib/ruby/vendor_ruby/spreadsheet/excel/writer/
/usr/lib/ruby/vendor_ruby/spreadsheet/excel/writer/biff8.rb
/usr/lib/ruby/vendor_ruby/spreadsheet/excel/writer/worksheet.rb
/usr/lib/ruby/vendor_ruby/spreadsheet/excel/writer/workbook.rb
/usr/lib/ruby/vendor_ruby/spreadsheet/excel/writer/format.rb
/usr/lib/ruby/vendor_ruby/spreadsheet/font.rb
/usr/lib/ruby/vendor_ruby/spreadsheet/row.rb
/usr/lib/ruby/vendor_ruby/spreadsheet/worksheet.rb
/usr/lib/ruby/vendor_ruby/spreadsheet/workbook.rb
/usr/lib/ruby/vendor_ruby/spreadsheet/encodings.rb
/usr/lib/ruby/vendor_ruby/spreadsheet/writer.rb
/usr/lib/ruby/vendor_ruby/spreadsheet/column.rb
/usr/lib/ruby/vendor_ruby/spreadsheet/link.rb
/usr/lib/ruby/vendor_ruby/spreadsheet/format.rb
/usr/lib/ruby/vendor_ruby/spreadsheet/helpers.rb
/usr/lib/ruby/vendor_ruby/spreadsheet/compatibility.rb
/usr/lib/ruby/vendor_ruby/spreadsheet/excel.rb
/usr/lib/ruby/vendor_ruby/spreadsheet/formula.rb
/usr/lib/ruby/vendor_ruby/parseexcel.rb
/usr/lib/ruby/vendor_ruby/spreadsheet.rb
/usr/lib/ruby/vendor_ruby/parseexcel/
/usr/lib/ruby/vendor_ruby/parseexcel/parser.rb
/usr/lib/ruby/vendor_ruby/parseexcel/parseexcel.rb