Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/STMicroelectronics/STM32U031/TIM3/TIM3_OR1#0x0
OCREF_CLR=B_0x0
TIM3 option register 1
Ocref_clr source selection
0 (B_0x0): COMP1 output is connected to the OCREF_CLR input
1 (B_0x1): COMP2 output is connected to the OCREF_CLR input
https://github.com/cmsis-svd/cmsis-svd-data