/usr/lib/ruby/ is in ruby-ms-rest 0.6.2-1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/
/usr/lib/ruby/vendor_ruby/ms_rest/
/usr/lib/ruby/vendor_ruby/ms_rest.rb
/usr/lib/ruby/vendor_ruby/ms_rest/credentials/
/usr/lib/ruby/vendor_ruby/ms_rest/credentials/basic_authentication_credentials.rb
/usr/lib/ruby/vendor_ruby/ms_rest/credentials/service_client_credentials.rb
/usr/lib/ruby/vendor_ruby/ms_rest/credentials/string_token_provider.rb
/usr/lib/ruby/vendor_ruby/ms_rest/credentials/token_credentials.rb
/usr/lib/ruby/vendor_ruby/ms_rest/credentials/token_provider.rb
/usr/lib/ruby/vendor_ruby/ms_rest/deserialization_error.rb
/usr/lib/ruby/vendor_ruby/ms_rest/http_operation_error.rb
/usr/lib/ruby/vendor_ruby/ms_rest/http_operation_request.rb
/usr/lib/ruby/vendor_ruby/ms_rest/http_operation_response.rb
/usr/lib/ruby/vendor_ruby/ms_rest/rest_error.rb
/usr/lib/ruby/vendor_ruby/ms_rest/retry_policy_middleware.rb
/usr/lib/ruby/vendor_ruby/ms_rest/serialization.rb
/usr/lib/ruby/vendor_ruby/ms_rest/service_client.rb
/usr/lib/ruby/vendor_ruby/ms_rest/validation_error.rb
/usr/lib/ruby/vendor_ruby/ms_rest/version.rb