Magento's deployment configuration consists of the module and environmental configuration for your installation. Magento's deployment configuration is divided between:

• <base dir>/app/etc/config.php, which contains the list of installed modules
• <base dir>/app/etc/env.php, which contains environment settings, such as:
  • Database credentials and connection settings
  • Cache storage settings
  • Enabled cache types
  • Your encryption key
  • Web routing parameters (base URLs, URL path to Magento Admin)
  • File system paths

Together, they are referred to as Magento's deployment configuration because they are created during installation and are required to start Magento.

Unlike other module configuration files, Magento's deployment configuration is loaded into memory when Magento initializes, is not merged with any other files, and cannot be extended. (config.php and env.php are merged with each other, however.)