/usr/lib/ruby/vendor_ruby/ is in ruby-docker-api 1.22.2-1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/docker/
/usr/lib/ruby/vendor_ruby/docker.rb
/usr/lib/ruby/vendor_ruby/docker/base.rb
/usr/lib/ruby/vendor_ruby/docker/connection.rb
/usr/lib/ruby/vendor_ruby/docker/container.rb
/usr/lib/ruby/vendor_ruby/docker/error.rb
/usr/lib/ruby/vendor_ruby/docker/event.rb
/usr/lib/ruby/vendor_ruby/docker/exec.rb
/usr/lib/ruby/vendor_ruby/docker/image.rb
/usr/lib/ruby/vendor_ruby/docker/messages.rb
/usr/lib/ruby/vendor_ruby/docker/messages_stack.rb
/usr/lib/ruby/vendor_ruby/docker/rake_task.rb
/usr/lib/ruby/vendor_ruby/docker/util.rb
/usr/lib/ruby/vendor_ruby/docker/version.rb
/usr/lib/ruby/vendor_ruby/excon/
/usr/lib/ruby/vendor_ruby/excon/middlewares/
/usr/lib/ruby/vendor_ruby/excon/middlewares/hijack.rb