/usr/lib/ruby/vendor_ruby/ is in ruby-librarian 0.1.1-2.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/librarian/dsl/
/usr/lib/ruby/vendor_ruby/librarian/mock/source/
/usr/lib/ruby/vendor_ruby/librarian/
/usr/lib/ruby/vendor_ruby/librarian/resolver.rb
/usr/lib/ruby/vendor_ruby/librarian/error.rb
/usr/lib/ruby/vendor_ruby/librarian/specfile.rb
/usr/lib/ruby/vendor_ruby/librarian/action/
/usr/lib/ruby/vendor_ruby/librarian/action/install.rb
/usr/lib/ruby/vendor_ruby/librarian/action/persist_resolution_mixin.rb
/usr/lib/ruby/vendor_ruby/librarian/action/resolve.rb
/usr/lib/ruby/vendor_ruby/librarian/action/update.rb
/usr/lib/ruby/vendor_ruby/librarian/action/clean.rb
/usr/lib/ruby/vendor_ruby/librarian/action/ensure.rb
/usr/lib/ruby/vendor_ruby/librarian/action/base.rb
/usr/lib/ruby/vendor_ruby/librarian/action.rb
/usr/lib/ruby/vendor_ruby/librarian/manifest.rb
/usr/lib/ruby/vendor_ruby/librarian/version.rb
/usr/lib/ruby/vendor_ruby/librarian/cli/
/usr/lib/ruby/vendor_ruby/librarian/cli/manifest_presenter.rb
/usr/lib/ruby/vendor_ruby/librarian/helpers.rb
/usr/lib/ruby/vendor_ruby/librarian/spec_change_set.rb
/usr/lib/ruby/vendor_ruby/librarian/dsl/target.rb
/usr/lib/ruby/vendor_ruby/librarian/dsl/receiver.rb
/usr/lib/ruby/vendor_ruby/librarian/lockfile/
/usr/lib/ruby/vendor_ruby/librarian/lockfile/parser.rb
/usr/lib/ruby/vendor_ruby/librarian/lockfile/compiler.rb
/usr/lib/ruby/vendor_ruby/librarian/ui.rb
/usr/lib/ruby/vendor_ruby/librarian/logger.rb
/usr/lib/ruby/vendor_ruby/librarian/config/
/usr/lib/ruby/vendor_ruby/librarian/config/database.rb
/usr/lib/ruby/vendor_ruby/librarian/config/file_source.rb
/usr/lib/ruby/vendor_ruby/librarian/config/hash_source.rb
/usr/lib/ruby/vendor_ruby/librarian/config/source.rb
/usr/lib/ruby/vendor_ruby/librarian/mock/
/usr/lib/ruby/vendor_ruby/librarian/mock/extension.rb
/usr/lib/ruby/vendor_ruby/librarian/mock/version.rb
/usr/lib/ruby/vendor_ruby/librarian/mock/dsl.rb
/usr/lib/ruby/vendor_ruby/librarian/mock/environment.rb
/usr/lib/ruby/vendor_ruby/librarian/mock/source/mock/
/usr/lib/ruby/vendor_ruby/librarian/mock/source/mock/registry.rb
/usr/lib/ruby/vendor_ruby/librarian/mock/source/mock.rb
/usr/lib/ruby/vendor_ruby/librarian/mock/cli.rb
/usr/lib/ruby/vendor_ruby/librarian/mock/source.rb
/usr/lib/ruby/vendor_ruby/librarian/dsl.rb
/usr/lib/ruby/vendor_ruby/librarian/config.rb
/usr/lib/ruby/vendor_ruby/librarian/linter/
/usr/lib/ruby/vendor_ruby/librarian/linter/source_linter.rb
/usr/lib/ruby/vendor_ruby/librarian/rspec/
/usr/lib/ruby/vendor_ruby/librarian/rspec/support/
/usr/lib/ruby/vendor_ruby/librarian/rspec/support/cli_macro.rb
/usr/lib/ruby/vendor_ruby/librarian/dependency.rb
/usr/lib/ruby/vendor_ruby/librarian/environment.rb
/usr/lib/ruby/vendor_ruby/librarian/support/
/usr/lib/ruby/vendor_ruby/librarian/support/abstract_method.rb
/usr/lib/ruby/vendor_ruby/librarian/spec.rb
/usr/lib/ruby/vendor_ruby/librarian/resolution.rb
/usr/lib/ruby/vendor_ruby/librarian/source/
/usr/lib/ruby/vendor_ruby/librarian/source/git.rb
/usr/lib/ruby/vendor_ruby/librarian/source/local.rb
/usr/lib/ruby/vendor_ruby/librarian/source/git/
/usr/lib/ruby/vendor_ruby/librarian/source/git/repository.rb
/usr/lib/ruby/vendor_ruby/librarian/source/basic_api.rb
/usr/lib/ruby/vendor_ruby/librarian/source/path.rb
/usr/lib/ruby/vendor_ruby/librarian/manifest_set.rb
/usr/lib/ruby/vendor_ruby/librarian/mock.rb
/usr/lib/ruby/vendor_ruby/librarian/cli.rb
/usr/lib/ruby/vendor_ruby/librarian/lockfile.rb
/usr/lib/ruby/vendor_ruby/librarian/source.rb
/usr/lib/ruby/vendor_ruby/librarian/resolver/
/usr/lib/ruby/vendor_ruby/librarian/resolver/implementation.rb
/usr/lib/ruby/vendor_ruby/librarian/posix.rb
/usr/lib/ruby/vendor_ruby/librarian.rb