CONFIG_ZSTD_DECOMPRESS (not configurable)

modulename: zstd_decompress.ko

configname: CONFIG_ZSTD_DECOMPRESS

Linux Kernel Configuration
└─>Library routines
└─>ZSTD_DECOMPRESS
In linux kernel since version 3.10 (release Date: 2013-06-30)  
source code:
lib/zstd/
selects
CONFIG_XXHASH

is depended by
CONFIG_SQUASHFS_ZSTD