drupal/core/modules/language/language.services.yml

services:
  path_processor_language:
    class: Drupal\language\HttpKernel\PathProcessorLanguage
    arguments: ['@config.factory', '@settings', '@language_manager']
    tags:
      - { name: path_processor_inbound, priority: 300 }
      - { name: path_processor_outbound, priority: 100 }