CONFIG_ETRAX_RESCUE_SER3 is not available for thedefaultarchitecture x86.
Result is shown for architecture cris
default or selected kernelversion does not have config value CONFIG_ETRAX_RESCUE_SER3.
Result is shown for kernelversion 6.7-rc3

Serial-3

configname: CONFIG_ETRAX_RESCUE_SER3

Product rescue-port
└─>Serial-3
In linux kernel since version 2.6.12  
Use serial port 3 as the rescue port.