CONFIG_DEBUG_BCMBCA is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
default or selected kernelversion does not have config value CONFIG_DEBUG_BCMBCA.
Result is shown for kernelversion 6.6.76

Kernel low-level debugging on BCMBCA UART0

modulename: board_bcmbca.ko

configname: CONFIG_DEBUG_BCMBCA

Kernel low-level debugging port
└─>Kernel low-level debugging on BCMBCA UART0
In linux kernel since version 6.13 (release Date: 2025-01-19)  
source code:
arch/arm/mach-bcm/board_bcmbca.c