Char sequence that enables magic SysRq over serial

configname: CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE

Linux Kernel Configuration
└─>Kernel hacking
└─>Generic Kernel Debugging Instruments
└─>Char sequence that enables magic SysRq over serial
In linux kernel since version 5.1 (release Date: 2019-05-05)  
Specifies a sequence of characters that can follow BREAK to enable
SysRq on a serial console.

If unsure, leave an empty string and the option will not be enabled.