Resolved as the environment name in deployments and in load execution.
Supported in deployments and in all loads.
Environment_name value is environment specific.
Environment_name value is transformed:
'-' and '.' are replaced with '_'
All characters are transformed to uppercase
Works like other variables in loads. See loadname for examples.
See CONFIG_ENTITY_PERMISSIONS for an example on how to use environment_name as part of grantee name to enable environment specific roles.