Was setting up script, sendmytip.sh, to update PoolTool with tip and height information.

I noticed this NODE_ID value:

#!/usr/bin/env bash

## CHANGE THESE TO SUITE YOUR POOL

# your pool id as on the explorer
PT_MY_POOL_ID="xxxx"
# get this from your account profile page on pooltool website
PT_MY_API_KEY="xxxx-xx-xx-xx-xxxx"
# Your node ID (optional, this is reserved for future use and is not captured yet)
PT_MY_NODE_ID="xxxx-xxx-xxx-xxx-xxxx"

It's the last line, and is clearly different from the Pool ID.

Would anyone care to let me know how to find a node id, or explain what they are?