The site directory structure will look something like this:

sites/library.test
├── locks
├── logs
├── private
│   ├── backups
│   └── files
├── public
│   └── files
├── site_config.json
└── task-logs

8 directories, 1 file

As you can see, the private folder will contain any database backups and private files. Private files are user uploaded files that need authentication to be accessible.

The public folder will contain files that are accessible without authentication. This can contain website images that should be accessible without login.

The site_config.json file contains configuration that is specific to this site which should not be version controlled. This is similar to an environment variables file. If you look at the contents of the file, it contains the database configuration values for this site.

{
 'db_name': '_ad03fa1a016ca1c4',
 'db_password': 'pz1d2gN5y35ydRO5',
 'db_type': 'mariadb'
}