/usr/lib/ is in ruby-markerb 1.1.0-2.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/
/usr/lib/ruby/vendor_ruby/
/usr/lib/ruby/vendor_ruby/generators/
/usr/lib/ruby/vendor_ruby/generators/markerb/
/usr/lib/ruby/vendor_ruby/generators/markerb/mailer/
/usr/lib/ruby/vendor_ruby/generators/markerb/mailer/templates/
/usr/lib/ruby/vendor_ruby/generators/markerb/mailer/templates/layout.markerb
/usr/lib/ruby/vendor_ruby/generators/markerb/mailer/templates/view.markerb
/usr/lib/ruby/vendor_ruby/generators/markerb/mailer/mailer_generator.rb
/usr/lib/ruby/vendor_ruby/markerb/
/usr/lib/ruby/vendor_ruby/markerb/markdown.rb
/usr/lib/ruby/vendor_ruby/markerb/railtie.rb
/usr/lib/ruby/vendor_ruby/markerb/version.rb
/usr/lib/ruby/vendor_ruby/markerb.rb