/usr/lib/ruby/vendor_ruby/ is in ruby-metriks 0.9.9.6-1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/metriks/
/usr/lib/ruby/vendor_ruby/metriks/exponentially_decaying_sample.rb
/usr/lib/ruby/vendor_ruby/metriks/timer.rb
/usr/lib/ruby/vendor_ruby/metriks/time_tracker.rb
/usr/lib/ruby/vendor_ruby/metriks/simple_moving_average.rb
/usr/lib/ruby/vendor_ruby/metriks/snapshot.rb
/usr/lib/ruby/vendor_ruby/metriks/ewma.rb
/usr/lib/ruby/vendor_ruby/metriks/gauge.rb
/usr/lib/ruby/vendor_ruby/metriks/registry.rb
/usr/lib/ruby/vendor_ruby/metriks/counter.rb
/usr/lib/ruby/vendor_ruby/metriks/utilization_timer.rb
/usr/lib/ruby/vendor_ruby/metriks/uniform_sample.rb
/usr/lib/ruby/vendor_ruby/metriks/reporter/
/usr/lib/ruby/vendor_ruby/metriks/reporter/graphite.rb
/usr/lib/ruby/vendor_ruby/metriks/reporter/librato_metrics.rb
/usr/lib/ruby/vendor_ruby/metriks/reporter/logger.rb
/usr/lib/ruby/vendor_ruby/metriks/reporter/riemann.rb
/usr/lib/ruby/vendor_ruby/metriks/reporter/proc_title.rb
/usr/lib/ruby/vendor_ruby/metriks/meter.rb
/usr/lib/ruby/vendor_ruby/metriks/histogram.rb
/usr/lib/ruby/vendor_ruby/metriks.rb