CONFIG_PFB is not available for thedefaultarchitecture x86.
Result is shown for architecture blackfin
default or selected kernelversion does not have config value CONFIG_PFB.
Result is shown for kernelversion 6.7-rc3

PF Interrupt B

configname: CONFIG_PFB

Linux Kernel Configuration
└─>BF533/2/1 Specific Configuration
└─>Priority
└─>PF Interrupt B
In linux kernel since version 2.6.22 (release Date: 2007-07-08)