Arduino for STM32

Your post made me think and I now realize that the serial programming connector on the board connects to PA9/PA10 UART pins and not the PA2/PA3 UART pins. So, even though I use the PA9 and PA10 pins for I2C, when in bootloader mode, the pullups don't affect the NRZ nature of the serial port. However ...

I am using the Generic STM32F0 Series / Genric F030K6Tx configuration. The variant_generic.h file used in the variant folder does include the typical Serial stuff with the correct RX/TX pin definitions. I can't however, figure out where the Serial object actually gets created. I see HardwareSerial ...

Crickets! So, does anyone know where in the Serial object is instantiated?

I am using Arduino IDE v2.3.2 with this basic STM32F030K6T6 from Aliexpres:

https://www.aliexpress.com/item/1005001960895226.html?spm=a2g0o.order_list.order_list_main.10.3fd81802kPAicZ

The board is set to "Generic STM32F0 series", the board part number is "Generic F030K6Tx" and I use ...