default_language.yml

id: default_language
label: Default language
migration_tags:
  - Drupal 6
  - Drupal 7
  - Configuration
source:
  plugin: variable
  variables:
    - language_default
  source_module: locale
process:
  default_langcode:
    -
      plugin: default_value
      source: language_default
      default_value:
        'language': 'en'
    # Encode and decode to turn the default_language variable, which is
    # an stdClass, into an array so it can be passed to extract.
    -
      plugin: callback
      callable:
        - '\Drupal\Component\Serialization\Json'
        - 'encode'
    -
      plugin: callback
      callable:
        - '\Drupal\Component\Serialization\Json'
        - 'decode'
    -
      plugin: extract
      index:
        - language
destination:
  plugin: default_langcode
  config_name: system.site
migration_dependencies:
  required:
    - language