/usr/lib/ruby/vendor_ruby/ is in ruby-celluloid 0.16.0-4.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/celluloid/
/usr/lib/ruby/vendor_ruby/celluloid/supervision_group.rb
/usr/lib/ruby/vendor_ruby/celluloid/receivers.rb
/usr/lib/ruby/vendor_ruby/celluloid/cpu_counter.rb
/usr/lib/ruby/vendor_ruby/celluloid/mailbox.rb
/usr/lib/ruby/vendor_ruby/celluloid/responses.rb
/usr/lib/ruby/vendor_ruby/celluloid/legacy.rb
/usr/lib/ruby/vendor_ruby/celluloid/condition.rb
/usr/lib/ruby/vendor_ruby/celluloid/registry.rb
/usr/lib/ruby/vendor_ruby/celluloid/rspec.rb
/usr/lib/ruby/vendor_ruby/celluloid/notifications.rb
/usr/lib/ruby/vendor_ruby/celluloid/pool_manager.rb
/usr/lib/ruby/vendor_ruby/celluloid/exceptions.rb
/usr/lib/ruby/vendor_ruby/celluloid/task_set.rb
/usr/lib/ruby/vendor_ruby/celluloid/logger.rb
/usr/lib/ruby/vendor_ruby/celluloid/logging/
/usr/lib/ruby/vendor_ruby/celluloid/logging/incident.rb
/usr/lib/ruby/vendor_ruby/celluloid/logging/incident_reporter.rb
/usr/lib/ruby/vendor_ruby/celluloid/logging/log_event.rb
/usr/lib/ruby/vendor_ruby/celluloid/logging/incident_logger.rb
/usr/lib/ruby/vendor_ruby/celluloid/logging/ring_buffer.rb
/usr/lib/ruby/vendor_ruby/celluloid/method.rb
/usr/lib/ruby/vendor_ruby/celluloid/stack_dump.rb
/usr/lib/ruby/vendor_ruby/celluloid/test.rb
/usr/lib/ruby/vendor_ruby/celluloid/cell.rb
/usr/lib/ruby/vendor_ruby/celluloid/core_ext.rb
/usr/lib/ruby/vendor_ruby/celluloid/internal_pool.rb
/usr/lib/ruby/vendor_ruby/celluloid/signals.rb
/usr/lib/ruby/vendor_ruby/celluloid/properties.rb
/usr/lib/ruby/vendor_ruby/celluloid/autostart.rb
/usr/lib/ruby/vendor_ruby/celluloid/system_events.rb
/usr/lib/ruby/vendor_ruby/celluloid/tasks.rb
/usr/lib/ruby/vendor_ruby/celluloid/uuid.rb
/usr/lib/ruby/vendor_ruby/celluloid/evented_mailbox.rb
/usr/lib/ruby/vendor_ruby/celluloid/links.rb
/usr/lib/ruby/vendor_ruby/celluloid/supervisor.rb
/usr/lib/ruby/vendor_ruby/celluloid/handlers.rb
/usr/lib/ruby/vendor_ruby/celluloid/thread.rb
/usr/lib/ruby/vendor_ruby/celluloid/fiber.rb
/usr/lib/ruby/vendor_ruby/celluloid/thread_handle.rb
/usr/lib/ruby/vendor_ruby/celluloid/rspec/
/usr/lib/ruby/vendor_ruby/celluloid/rspec/example_actor_class.rb
/usr/lib/ruby/vendor_ruby/celluloid/rspec/task_examples.rb
/usr/lib/ruby/vendor_ruby/celluloid/rspec/mailbox_examples.rb
/usr/lib/ruby/vendor_ruby/celluloid/rspec/actor_examples.rb
/usr/lib/ruby/vendor_ruby/celluloid/call_chain.rb
/usr/lib/ruby/vendor_ruby/celluloid/actor.rb
/usr/lib/ruby/vendor_ruby/celluloid/calls.rb
/usr/lib/ruby/vendor_ruby/celluloid/actor_system.rb
/usr/lib/ruby/vendor_ruby/celluloid/probe.rb
/usr/lib/ruby/vendor_ruby/celluloid/logging.rb
/usr/lib/ruby/vendor_ruby/celluloid/fsm.rb
/usr/lib/ruby/vendor_ruby/celluloid/tasks/
/usr/lib/ruby/vendor_ruby/celluloid/tasks/task_thread.rb
/usr/lib/ruby/vendor_ruby/celluloid/tasks/task_fiber.rb
/usr/lib/ruby/vendor_ruby/celluloid/proxies/
/usr/lib/ruby/vendor_ruby/celluloid/proxies/sync_proxy.rb
/usr/lib/ruby/vendor_ruby/celluloid/proxies/abstract_proxy.rb
/usr/lib/ruby/vendor_ruby/celluloid/proxies/actor_proxy.rb
/usr/lib/ruby/vendor_ruby/celluloid/proxies/async_proxy.rb
/usr/lib/ruby/vendor_ruby/celluloid/proxies/block_proxy.rb
/usr/lib/ruby/vendor_ruby/celluloid/proxies/future_proxy.rb
/usr/lib/ruby/vendor_ruby/celluloid/proxies/cell_proxy.rb
/usr/lib/ruby/vendor_ruby/celluloid/future.rb
/usr/lib/ruby/vendor_ruby/celluloid.rb