How to unset a variable which is previously set somewhere in Mac OS I don't know?

Question

I have a variable set exactly like this:

export VARIABLE_NAME=VARIABLE_VALUE

I thought it would be in ~/.zshrc or bash_profile but it is seen in none of those. I am now struggling to understand where its getting set and I want to reset it up. Can someone suggest easy way to do so? I am on MacOS

I am using zsh shell. I know the command called unset VARIABLE_NAME. However I am looking into finding root cause and removing the variable from the first place where its been set.

Variable name is JWT_SECRET

Update:

I tried running grep JWT_SECRET {~/.z,/etc/z}{shenv,profile,shrc,login} as proposed by @nohillside

I have configured my zsh to use ohmyzsh.

Here's how output looks like:

When I do: echo $SHELL $ZSH_VERSION $BASH_VERSION I get: /bin/zsh 5.9

Here's what I have in my ~/.zshrc:

export NVM_DIR="$HOME/.nvm"
[ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"  # This loads nvm
DISABLE_AUTO_TITLE="true"
PS1="%1d %& # "
export ZSH="$HOME/.oh-my-zsh"
ZSH_THEME="robbyrussell"
ENABLE_CORRECTION="true"
plugins=(git)
source $ZSH/oh-my-zsh.sh
export SU_PASSWORD=<PASSWORD>
export SU_USERNAME=<USERNAME>
export PATH="/Users/<username>/bin:$PATH"

Answer 1

This variable can be set in any of the files zsh reads at startup, or in any command called from one of these files. According to the man page, these are (with ZDOTDIR defaulting to HOME)

$ZDOTDIR/.zshenv
$ZDOTDIR/.zprofile
$ZDOTDIR/.zshrc
$ZDOTDIR/.zlogin
/etc/zshenv
/etc/zprofile
/etc/zshrc
/etc/zlogin

So as a first attempt, run

grep JWT_SECRET {~/.z,/etc/z}{shenv,profile,shrc,login}

Ignore any "file not found" errors, and check whether it returns a match. If it doesn't, you need to manually look at each of these files (if they exist) and check for any commands which could actually set the variable.