Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Silicon Labs/Series1/WGM160/WGM160PX22KGA2/QSPI0/OPCODEEXTUPPER#0x0
Opcode Extension Register (Upper)
WEL Opcode Extension
WEL Opcode
https://github.com/cmsis-svd/cmsis-svd-data