Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/STMicroelectronics/STM32H7x5_CM7/MDIOS/MDIOS_DOUTR9#0x0
MDIOS output data register 9
Output data sent to MDIO Master during read frames
https://github.com/cmsis-svd/cmsis-svd-data