Another bit of info from the Arduino web site on the Uno WiFi: Serial ports The Arduino Uno WiFi Rev. 2 has 3 hardware serial ports. Serial is connected to the USB interface, Serial1 is connected to Pin 0 (RX) and 1 (TX), Serial 2 is connected to the u-blox NINA-W13 module. This allows the usage of pins 0 and 1 without issues: on the original Arduino UNO, the usage of Pins 0 and 1 disrupts the sketch upload.
More info on the Arduino Uno WiFi Rev2: This board uses the new Microchip MEGA4809 microcontroller that has a different memory layout compared to the usual ATmega 328P. You now have 48K of Flash memory, 6K of RAM and 256 bytes of EEPROM, therefore you have more Flash and more memory than the Arduino UNO (16K Flash and 2K RAM). The programming of the MEGA4809 happens through an ATmega 32U4 programmed with the mDBG code and creates a virtual COM port when connected to a PC. Serial ports The Arduino Uno WiFi Rev. 2 has 3 hardware serial ports. Serial is connected to the USB interface, Serial1 is connected to Pin 0 (RX) and 1 (TX), Serial 2 is connected to the u-blox NINA-W13 module. This allows the usage of pins 0 and 1 without issues: on the original Arduino UNO, the usage of Pins 0 and 1 disrupts the sketch upload. SPI The SPI interface is available on the ICSP connector with the usual layout for MISO, MOSI, SCK and CS. The IMU and the WiFi module are connected to the SPI bus and have individuale and dedicated pins for Chip Select (CS) Analog The new core has 5 PWM pins and the pin 11 doesn't support PWM. The resolution of the 6 A/D pins is the usual, with 10 bits and values from 0 to 1023. RGB LED Close to the Nina module and the ICSP connector there is a square RGB SMD LED. This LED is directly connected to the NINA-W13 WiFi module and it is driven by the module itself. It will be used for future applications and developments. Integrated IMU On the SPI bus, with a dedicated CS connection (pin D30 or SPIIMU_SS) and a dedicated interrupt pin (SPIIMU_INT), the Arduino UNO WiFi Rev.2 has a LSM6DS IMU with 3-axis accelerometer and 3-axis gyroscope. This chip made by ST Microelectronics is a standard component already supported by many libraries; you can choose between the available ones in our library manager using LSM6DS keyword. Interrupts The new MEGA4809 microcontroller allows you to attach any digital pin to an interrupt, therefore you may have as many Interrupt Service Routines (ISR) as the available digital pins. You still define the interrupts with the usual function attachInterrupt(digitalPinToInterrupt(pin), ISR, mode);. Please refer to the attachInterrupt() page for further details. Note: the WiFi antenna built in in the U-blox NINA-W13 module is made for embedded products and should NOT be touched. Applying pressure or force on it could cause damage. Be very careful when you detach shields on this board because you may pull the WiFi antenna.
If I had the hardware and the spare time to dive into it I would. But I'm currently focused solely on my ESP32 Command Station code and trying to get back to working on my layout (it has been ~2 1/2mo since I've done anything on it!)
