Enviro Grow web hook authentication

Hello!
I’ve got a codey type problem if anyone can help? It’s a Python, Weebhook, NodeJS, API, Google Cloud thing.

I’ve got an Enviro Grow provisioned to send updates to a custom API.

I want to use custom_http_username & custom_http_password to send credential information to my API so that I can authenticate the request. eg…

config.py

# web hook settings
custom_http_url = 'https://api.listingslab.com/stumpy'
custom_http_username = 'aa88d1d5-8632-4a20-a1d2-d91d86078c37'
custom_http_password = '58235fe5-b321-4fa2-a369-11c3b6608163'

The webhook post request gets made in this file, /enviro/destinations/http.py and all that works great but what I can’t work out is how to access the username & password in my API’s Node function

export const webhookStumpy = async (
    req: functions.https.Request,
    firebaseApp: firebase.FirebaseApp,
) => {
    // what do I pull out here? headers? auth? any ideas?
    const {body, method} = req;
}

How is the custom auth information attached to the post request please?