Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/STMicroelectronics/STM32U599/USART1/RQR#0x0
Request register
Auto baud rate request
Send break request
Mute mode request
Receive data flush request
Transmit data flush request
https://github.com/cmsis-svd/cmsis-svd-data