Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32n6/STM32N645/DMA2D/DMA2D_BGCLUT221#0x0
DMA2D background CLUT
Blue
Green
Red
Alpha
https://github.com/modm-io/cmsis-svd-stm32