/usr/lib/ is in ruby-clockwork 1.2.0-3.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/
/usr/lib/ruby/vendor_ruby/
/usr/lib/ruby/vendor_ruby/clockwork/
/usr/lib/ruby/vendor_ruby/clockwork/database_events/
/usr/lib/ruby/vendor_ruby/clockwork/database_events/sync_performer.rb
/usr/lib/ruby/vendor_ruby/clockwork/database_events/manager.rb
/usr/lib/ruby/vendor_ruby/clockwork/database_events/event.rb
/usr/lib/ruby/vendor_ruby/clockwork/database_events/registry.rb
/usr/lib/ruby/vendor_ruby/clockwork/manager.rb
/usr/lib/ruby/vendor_ruby/clockwork/database_events.rb
/usr/lib/ruby/vendor_ruby/clockwork/event.rb
/usr/lib/ruby/vendor_ruby/clockwork/at.rb
/usr/lib/ruby/vendor_ruby/clockwork.rb