CONFIG_ETRAX_LED3R is not available for thedefaultarchitecture x86.
Result is shown for architecture cris
default or selected kernelversion does not have config value CONFIG_ETRAX_LED3R.
Result is shown for kernelversion 6.7-rc3

Third red LED bit

configname: CONFIG_ETRAX_LED3R

Linux Kernel Configuration
└─>CRIS v10 options
└─>Third red LED bit
In linux kernel since version 2.6.12  
Bit to use for the third red LED.
For products with only one or two controllable LEDs,
set this to same as CONFIG_ETRAX_LED1G (normally 2).