Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Silicon Labs/Series1/EFM32GG11B/EFM32GG11B520F2048GQ100/UART1/RXDATAX#0x0
RX Buffer Data Extended Register
RX Data
Data Parity Error
Data Framing Error
https://github.com/cmsis-svd/cmsis-svd-data