Where should that file go in the *nix filesystem?

FHS v2.3

Directory Description
bin essential binaries
boot boot loader
dev device files
etc host-specific system configuration
home user home directories (optional)
lib shared libraries/kernel modules
media removable media mount point
mnt temporary filesystem mount point
opt add-on software packages
root home directory for the root user (optional)
sbin essential system binaries
srv data for services provided by this system
tmp temporary files
usr secondary hierarchy
var variable data

source