/usr/lib/ is in ruby-hamster 3.0.0-2.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/
/usr/lib/ruby/vendor_ruby/
/usr/lib/ruby/vendor_ruby/hamster/
/usr/lib/ruby/vendor_ruby/hamster/associable.rb
/usr/lib/ruby/vendor_ruby/hamster/core_ext/
/usr/lib/ruby/vendor_ruby/hamster/core_ext/enumerable.rb
/usr/lib/ruby/vendor_ruby/hamster/core_ext/io.rb
/usr/lib/ruby/vendor_ruby/hamster/core_ext/struct.rb
/usr/lib/ruby/vendor_ruby/hamster/core_ext.rb
/usr/lib/ruby/vendor_ruby/hamster/deque.rb
/usr/lib/ruby/vendor_ruby/hamster/enumerable.rb
/usr/lib/ruby/vendor_ruby/hamster/experimental/
/usr/lib/ruby/vendor_ruby/hamster/experimental/mutable_queue.rb
/usr/lib/ruby/vendor_ruby/hamster/experimental/mutable_set.rb
/usr/lib/ruby/vendor_ruby/hamster/hash.rb
/usr/lib/ruby/vendor_ruby/hamster/immutable.rb
/usr/lib/ruby/vendor_ruby/hamster/list.rb
/usr/lib/ruby/vendor_ruby/hamster/mutable_hash.rb
/usr/lib/ruby/vendor_ruby/hamster/nested.rb
/usr/lib/ruby/vendor_ruby/hamster/read_copy_update.rb
/usr/lib/ruby/vendor_ruby/hamster/set.rb
/usr/lib/ruby/vendor_ruby/hamster/sorted_set.rb
/usr/lib/ruby/vendor_ruby/hamster/trie.rb
/usr/lib/ruby/vendor_ruby/hamster/undefined.rb
/usr/lib/ruby/vendor_ruby/hamster/vector.rb
/usr/lib/ruby/vendor_ruby/hamster/version.rb
/usr/lib/ruby/vendor_ruby/hamster.rb