Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Silicon Labs/Series0/EZR32WG/EZR32WG330F256R63/USART1/RXDATAXP#0x0
RX Buffer Data Extended Peek Register
RX Data Peek
Data Parity Error Peek
Data Framing Error Peek
https://github.com/cmsis-svd/cmsis-svd-data