/usr/lib/ruby/ is in ruby-nenv 0.3.0-2.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/
/usr/lib/ruby/vendor_ruby/nenv/
/usr/lib/ruby/vendor_ruby/nenv/autoenvironment.rb
/usr/lib/ruby/vendor_ruby/nenv/builder.rb
/usr/lib/ruby/vendor_ruby/nenv/environment/
/usr/lib/ruby/vendor_ruby/nenv/environment/dumper/
/usr/lib/ruby/vendor_ruby/nenv/environment/dumper/default.rb
/usr/lib/ruby/vendor_ruby/nenv/environment/dumper.rb
/usr/lib/ruby/vendor_ruby/nenv/environment/loader/
/usr/lib/ruby/vendor_ruby/nenv/environment/loader/default.rb
/usr/lib/ruby/vendor_ruby/nenv/environment/loader/predicate.rb
/usr/lib/ruby/vendor_ruby/nenv/environment/loader.rb
/usr/lib/ruby/vendor_ruby/nenv/environment.rb
/usr/lib/ruby/vendor_ruby/nenv/version.rb
/usr/lib/ruby/vendor_ruby/nenv.rb