/usr/lib/ruby/vendor_ruby/ is in ruby-httpclient 2.8.3-1ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/hexdump.rb
/usr/lib/ruby/vendor_ruby/http-access2/
/usr/lib/ruby/vendor_ruby/http-access2.rb
/usr/lib/ruby/vendor_ruby/http-access2/cookie.rb
/usr/lib/ruby/vendor_ruby/http-access2/http.rb
/usr/lib/ruby/vendor_ruby/httpclient/
/usr/lib/ruby/vendor_ruby/httpclient.rb
/usr/lib/ruby/vendor_ruby/httpclient/auth.rb
/usr/lib/ruby/vendor_ruby/httpclient/cacert.pem
/usr/lib/ruby/vendor_ruby/httpclient/cacert1024.pem
/usr/lib/ruby/vendor_ruby/httpclient/connection.rb
/usr/lib/ruby/vendor_ruby/httpclient/cookie.rb
/usr/lib/ruby/vendor_ruby/httpclient/http.rb
/usr/lib/ruby/vendor_ruby/httpclient/include_client.rb
/usr/lib/ruby/vendor_ruby/httpclient/jruby_ssl_socket.rb
/usr/lib/ruby/vendor_ruby/httpclient/session.rb
/usr/lib/ruby/vendor_ruby/httpclient/ssl_config.rb
/usr/lib/ruby/vendor_ruby/httpclient/ssl_socket.rb
/usr/lib/ruby/vendor_ruby/httpclient/timeout.rb
/usr/lib/ruby/vendor_ruby/httpclient/util.rb
/usr/lib/ruby/vendor_ruby/httpclient/version.rb
/usr/lib/ruby/vendor_ruby/httpclient/webagent-cookie.rb
/usr/lib/ruby/vendor_ruby/jsonclient.rb
/usr/lib/ruby/vendor_ruby/oauthclient.rb