/usr/lib/ruby/ is in ruby-zentest 4.11.0-2.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/
/usr/lib/ruby/vendor_ruby/autotest/
/usr/lib/ruby/vendor_ruby/autotest/once.rb
/usr/lib/ruby/vendor_ruby/autotest/preload.rb
/usr/lib/ruby/vendor_ruby/autotest/timestamp.rb
/usr/lib/ruby/vendor_ruby/autotest/isolate.rb
/usr/lib/ruby/vendor_ruby/autotest/bundler.rb
/usr/lib/ruby/vendor_ruby/autotest/restart.rb
/usr/lib/ruby/vendor_ruby/autotest/rcov.rb
/usr/lib/ruby/vendor_ruby/autotest/autoupdate.rb
/usr/lib/ruby/vendor_ruby/focus.rb
/usr/lib/ruby/vendor_ruby/functional_test_matrix.rb
/usr/lib/ruby/vendor_ruby/zentest_mapping.rb
/usr/lib/ruby/vendor_ruby/unit_diff.rb
/usr/lib/ruby/vendor_ruby/multiruby.rb
/usr/lib/ruby/vendor_ruby/autotest.rb
/usr/lib/ruby/vendor_ruby/zentest.rb