/usr/lib/ruby/vendor_ruby/treetop/compiler/node_classes/ is in ruby-treetop 1.4.10-5.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/treetop/compiler/node_classes/anything_symbol.rb
/usr/lib/ruby/vendor_ruby/treetop/compiler/node_classes/atomic_expression.rb
/usr/lib/ruby/vendor_ruby/treetop/compiler/node_classes/character_class.rb
/usr/lib/ruby/vendor_ruby/treetop/compiler/node_classes/choice.rb
/usr/lib/ruby/vendor_ruby/treetop/compiler/node_classes/declaration_sequence.rb
/usr/lib/ruby/vendor_ruby/treetop/compiler/node_classes/grammar.rb
/usr/lib/ruby/vendor_ruby/treetop/compiler/node_classes/inline_module.rb
/usr/lib/ruby/vendor_ruby/treetop/compiler/node_classes/nonterminal.rb
/usr/lib/ruby/vendor_ruby/treetop/compiler/node_classes/optional.rb
/usr/lib/ruby/vendor_ruby/treetop/compiler/node_classes/parenthesized_expression.rb
/usr/lib/ruby/vendor_ruby/treetop/compiler/node_classes/parsing_expression.rb
/usr/lib/ruby/vendor_ruby/treetop/compiler/node_classes/parsing_rule.rb
/usr/lib/ruby/vendor_ruby/treetop/compiler/node_classes/predicate.rb
/usr/lib/ruby/vendor_ruby/treetop/compiler/node_classes/predicate_block.rb
/usr/lib/ruby/vendor_ruby/treetop/compiler/node_classes/repetition.rb
/usr/lib/ruby/vendor_ruby/treetop/compiler/node_classes/sequence.rb
/usr/lib/ruby/vendor_ruby/treetop/compiler/node_classes/terminal.rb
/usr/lib/ruby/vendor_ruby/treetop/compiler/node_classes/transient_prefix.rb
/usr/lib/ruby/vendor_ruby/treetop/compiler/node_classes/treetop_file.rb