/usr/ is in ruby-json 1.8.0-1build1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/
/usr/lib/x86_64-linux-gnu/
/usr/lib/x86_64-linux-gnu/ruby/
/usr/lib/x86_64-linux-gnu/ruby/vendor_ruby/
/usr/lib/x86_64-linux-gnu/ruby/vendor_ruby/2.0.0/
/usr/lib/x86_64-linux-gnu/ruby/vendor_ruby/2.0.0/json/
/usr/lib/x86_64-linux-gnu/ruby/vendor_ruby/2.0.0/json/ext/
/usr/lib/x86_64-linux-gnu/ruby/vendor_ruby/2.0.0/json/ext/generator.so
/usr/lib/x86_64-linux-gnu/ruby/vendor_ruby/2.0.0/json/ext/parser.so
/usr/lib/ruby/
/usr/lib/ruby/vendor_ruby/
/usr/lib/ruby/vendor_ruby/1.9.1/
/usr/lib/ruby/vendor_ruby/1.9.1/x86_64-linux/
/usr/lib/ruby/vendor_ruby/1.9.1/x86_64-linux/json/
/usr/lib/ruby/vendor_ruby/1.9.1/x86_64-linux/json/ext/
/usr/lib/ruby/vendor_ruby/1.9.1/x86_64-linux/json/ext/generator.so
/usr/lib/ruby/vendor_ruby/1.9.1/x86_64-linux/json/ext/parser.so
/usr/lib/ruby/vendor_ruby/json.rb
/usr/lib/ruby/vendor_ruby/json/
/usr/lib/ruby/vendor_ruby/json/ext.rb
/usr/lib/ruby/vendor_ruby/json/pure.rb
/usr/lib/ruby/vendor_ruby/json/add/
/usr/lib/ruby/vendor_ruby/json/add/struct.rb
/usr/lib/ruby/vendor_ruby/json/add/date_time.rb
/usr/lib/ruby/vendor_ruby/json/add/date.rb
/usr/lib/ruby/vendor_ruby/json/add/ostruct.rb
/usr/lib/ruby/vendor_ruby/json/add/exception.rb
/usr/lib/ruby/vendor_ruby/json/add/core.rb
/usr/lib/ruby/vendor_ruby/json/add/regexp.rb
/usr/lib/ruby/vendor_ruby/json/add/time.rb
/usr/lib/ruby/vendor_ruby/json/add/symbol.rb
/usr/lib/ruby/vendor_ruby/json/add/complex.rb
/usr/lib/ruby/vendor_ruby/json/add/range.rb
/usr/lib/ruby/vendor_ruby/json/add/bigdecimal.rb
/usr/lib/ruby/vendor_ruby/json/add/rational.rb
/usr/lib/ruby/vendor_ruby/json/version.rb
/usr/lib/ruby/vendor_ruby/json/generic_object.rb
/usr/lib/ruby/vendor_ruby/json/pure/
/usr/lib/ruby/vendor_ruby/json/pure/parser.rb
/usr/lib/ruby/vendor_ruby/json/pure/generator.rb
/usr/lib/ruby/vendor_ruby/json/common.rb
/usr/share/
/usr/share/rubygems-integration/
/usr/share/rubygems-integration/1.9.1/
/usr/share/rubygems-integration/1.9.1/specifications/
/usr/share/rubygems-integration/1.9.1/specifications/json-1.8.0.gemspec
/usr/share/rubygems-integration/2.0/
/usr/share/rubygems-integration/2.0/specifications/
/usr/share/rubygems-integration/2.0/specifications/json-1.8.0.gemspec
/usr/share/doc/
/usr/share/doc/ruby-json/
/usr/share/doc/ruby-json/copyright
/usr/share/doc/ruby-json/README-json-jruby.markdown
/usr/share/doc/ruby-json/README.rdoc.gz
/usr/share/doc/ruby-json/examples/
/usr/share/doc/ruby-json/examples/fuzz.rb
/usr/share/doc/ruby-json/examples/server.rb
/usr/share/doc/ruby-json/changelog.Debian.gz