CONFIG_HARDEN_EL2_VECTORS is not available for thedefaultarchitecture x86.
Result is shown for architecture arm64
default or selected kernelversion does not have config value CONFIG_HARDEN_EL2_VECTORS.
Result is shown for kernelversion 6.9.9

Harden EL2 vector mapping against system register leak

configname: CONFIG_HARDEN_EL2_VECTORS

Linux Kernel Configuration
└─>Kernel Features
└─>Harden EL2 vector mapping against system register leak
In linux kernel since version 4.2 (release Date: 2015-08-30)  
Speculation attacks against some high-performance processors can
be used to leak privileged information such as the vector base
register, resulting in a potential defeat of the EL2 layout
randomization.

This config option will map the vectors to a fixed location,
independent of the EL2 code mapping, so that revealing VBAR_EL2
to an attacker does not give away any extra information. This
only gets enabled on affected CPUs.

If unsure, say Y.