/usr/lib/ruby/vendor_ruby/ is in vim-addon-manager 0.5.5.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/vim/
/usr/lib/ruby/vendor_ruby/vim/addon_manager/
/usr/lib/ruby/vendor_ruby/vim/addon_manager/registry.rb
/usr/lib/ruby/vendor_ruby/vim/addon_manager/addon_status.rb
/usr/lib/ruby/vendor_ruby/vim/addon_manager/logger.rb
/usr/lib/ruby/vendor_ruby/vim/addon_manager/constants.rb
/usr/lib/ruby/vendor_ruby/vim/addon_manager/upgrade_from_legacy.rb
/usr/lib/ruby/vendor_ruby/vim/addon_manager/addon/
/usr/lib/ruby/vendor_ruby/vim/addon_manager/addon/legacy.rb
/usr/lib/ruby/vendor_ruby/vim/addon_manager/addon/directory.rb
/usr/lib/ruby/vendor_ruby/vim/addon_manager/addon.rb
/usr/lib/ruby/vendor_ruby/vim/addon_manager/version.rb
/usr/lib/ruby/vendor_ruby/vim/addon_manager.rb