The Arduino Uno-compatible board has an MCS-51 (often called 8051 instead) instead of the usual ATmega328P/ATmega168. Specifically, [ElectroBoy] uses the AT89S52 .

Using the WiFi option, users can connect to the Arduino Cloud or other platforms to easily create connected projects.” To learn more about the UNO R4, please visit https://store.arduino.cc/pages ...