/usr/lib/ruby/vendor_ruby/ is in ruby-rspec-mocks 2.14.5-1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/rspec/
/usr/lib/ruby/vendor_ruby/rspec/mocks.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/
/usr/lib/ruby/vendor_ruby/rspec/mocks/targets.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/any_instance/
/usr/lib/ruby/vendor_ruby/rspec/mocks/any_instance/stub_chain_chain.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/any_instance/expectation_chain.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/any_instance/chain.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/any_instance/stub_chain.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/any_instance/message_chains.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/any_instance/recorder.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/extensions/
/usr/lib/ruby/vendor_ruby/rspec/mocks/extensions/marshal.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/extensions/instance_exec.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/example_methods.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/matchers/
/usr/lib/ruby/vendor_ruby/rspec/mocks/matchers/receive.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/matchers/have_received.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/configuration.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/errors.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/error_generator.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/proxy_for_nil.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/instance_method_stasher.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/method_double.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/argument_matchers.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/test_double.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/mock.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/deprecation.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/stub_chain.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/proxy.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/standalone.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/framework.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/space.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/order_group.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/version.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/syntax.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/argument_list_matcher.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/message_expectation.rb
/usr/lib/ruby/vendor_ruby/rspec/mocks/mutate_const.rb
/usr/lib/ruby/vendor_ruby/spec/
/usr/lib/ruby/vendor_ruby/spec/mocks.rb