CONFIG_DN_SERIAL is not available for thedefaultarchitecture x86.
Result is shown for architecture m68k
default or selected kernelversion does not have config value CONFIG_DN_SERIAL.
Result is shown for kernelversion 6.2.5

Support for DN serial port (dummy)

configname: CONFIG_DN_SERIAL

Linux Kernel Configuration
└─>Character devices
└─>Support for DN serial port (dummy)
In linux kernel since version 2.6.12