/usr/lib/ruby/vendor_ruby/ is in ruby-em-http-request 1.1.2-2.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/em-http.rb
/usr/lib/ruby/vendor_ruby/em-http/
/usr/lib/ruby/vendor_ruby/em-http/version.rb
/usr/lib/ruby/vendor_ruby/em-http/multi.rb
/usr/lib/ruby/vendor_ruby/em-http/request.rb
/usr/lib/ruby/vendor_ruby/em-http/decoders.rb
/usr/lib/ruby/vendor_ruby/em-http/http_client_options.rb
/usr/lib/ruby/vendor_ruby/em-http/http_connection.rb
/usr/lib/ruby/vendor_ruby/em-http/client.rb
/usr/lib/ruby/vendor_ruby/em-http/http_header.rb
/usr/lib/ruby/vendor_ruby/em-http/http_connection_options.rb
/usr/lib/ruby/vendor_ruby/em-http/http_encoding.rb
/usr/lib/ruby/vendor_ruby/em-http/http_status_codes.rb
/usr/lib/ruby/vendor_ruby/em-http/middleware/
/usr/lib/ruby/vendor_ruby/em-http/middleware/oauth.rb
/usr/lib/ruby/vendor_ruby/em-http/middleware/digest_auth.rb
/usr/lib/ruby/vendor_ruby/em-http/middleware/json_response.rb
/usr/lib/ruby/vendor_ruby/em-http/middleware/oauth2.rb
/usr/lib/ruby/vendor_ruby/em-http/core_ext/
/usr/lib/ruby/vendor_ruby/em-http/core_ext/bytesize.rb
/usr/lib/ruby/vendor_ruby/em-http-request.rb