/usr/ is in ruby-fakeweb 1.3.0+git20170806+dfsg1-1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/
/usr/lib/ruby/vendor_ruby/
/usr/lib/
/usr/lib/ruby/vendor_ruby/fake_web/
/usr/lib/ruby/vendor_ruby/fake_web/ext/
/usr/lib/ruby/vendor_ruby/fake_web/ext/net_http.rb
/usr/lib/ruby/vendor_ruby/fake_web/registry.rb
/usr/lib/ruby/vendor_ruby/fake_web/responder.rb
/usr/lib/ruby/vendor_ruby/fake_web/response.rb
/usr/lib/ruby/vendor_ruby/fake_web/stub_socket.rb
/usr/lib/ruby/vendor_ruby/fake_web/utility.rb
/usr/lib/ruby/vendor_ruby/fake_web.rb
/usr/lib/ruby/vendor_ruby/fakeweb.rb
/usr/share/
/usr/share/doc/
/usr/share/doc/ruby-fakeweb/
/usr/share/doc/ruby-fakeweb/README.rdoc.gz
/usr/share/doc/ruby-fakeweb/changelog.Debian.gz
/usr/share/doc/ruby-fakeweb/copyright
/usr/share/rubygems-integration/
/usr/share/rubygems-integration/all/
/usr/share/rubygems-integration/all/specifications/
/usr/share/rubygems-integration/all/specifications/fakeweb-1.3.0.gemspec