/usr/lib/ruby/vendor_ruby/mechanize/form/ is in ruby-mechanize 2.7.2-1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/mechanize/form/button.rb
/usr/lib/ruby/vendor_ruby/mechanize/form/check_box.rb
/usr/lib/ruby/vendor_ruby/mechanize/form/field.rb
/usr/lib/ruby/vendor_ruby/mechanize/form/file_upload.rb
/usr/lib/ruby/vendor_ruby/mechanize/form/hidden.rb
/usr/lib/ruby/vendor_ruby/mechanize/form/image_button.rb
/usr/lib/ruby/vendor_ruby/mechanize/form/keygen.rb
/usr/lib/ruby/vendor_ruby/mechanize/form/multi_select_list.rb
/usr/lib/ruby/vendor_ruby/mechanize/form/option.rb
/usr/lib/ruby/vendor_ruby/mechanize/form/radio_button.rb
/usr/lib/ruby/vendor_ruby/mechanize/form/reset.rb
/usr/lib/ruby/vendor_ruby/mechanize/form/select_list.rb
/usr/lib/ruby/vendor_ruby/mechanize/form/submit.rb
/usr/lib/ruby/vendor_ruby/mechanize/form/text.rb
/usr/lib/ruby/vendor_ruby/mechanize/form/textarea.rb