What you can see here
This adds some Netlify lambda functions to the project.
They will be triggered automatically once a new deploy starts, fails or succeeds. They currently send out notifications using Telegram.
In order to test it locally you'll need to setup a
.env.local file with the corresponding API token and chat ID.
To make it work on Netlify you'll neet to setup the values as environment variables.
Netlify Lambda Functions: https://www.netlify.com/docs/functions/
Telegram Bots API: https://core.telegram.org/bots/api