The dotenv or .env file is a file that contains environment va | Linux and DevOps books

The dotenv or .env file is a file that contains environment variables for your app. This may include sensitive information that you do not wish to disclose in your code. Therefore, since the file is human-readable, you should avoid committing .env files to version control systems such as GitHub. (This repository has a dummy one as a sample, but you should not commit it.)
https://github.com/Baelfire18/read-dotenv-files