CONFIG_CMDLINE_BOOTLOADER is not available for thedefaultarchitecture x86.
Result is shown for architecture loongarch

Use bootloader kernel arguments if available

configname: CONFIG_CMDLINE_BOOTLOADER

Kernel command line type
└─>Use bootloader kernel arguments if available
In linux kernel since version 5.2 (release Date: 2019-07-07)  
Prefer the command-line passed by the boot loader if available.
Use the built-in command line as fallback in case we get nothing
during boot. This is the default behaviour.