CONFIG_RISCV_ISA_VENDOR_EXT_THEAD is not available for thedefaultarchitecture x86.
Result is shown for architecture riscv

T-Head vendor extension support

modulename: thead.ko

and/or

thead_hwprobe.ko

configname: CONFIG_RISCV_ISA_VENDOR_EXT_THEAD

Linux Kernel Configuration
└─>Vendor extensions
└─>T-Head
└─>T-Head vendor extension support
In linux kernel since version 6.6.78 (release Date: 2025-02-17)  
Say N here to disable detection of and support for all T-Head vendor
extensions. Without this option enabled, T-Head vendor extensions will
not be detected at boot and their presence not reported to userspace.

If you don't know what to do here, say Y.

source code: