custom_field-1.0.x-dev/modules/custom_field_media/custom_field_media.services.yml

services:
  _defaults:
    autoconfigure: true
  custom_field_media.opener.form_element:
    class: Drupal\custom_field_media\MediaLibraryOpener
    arguments:
      - '@entity_type.manager'

  Drupal\custom_field_media\Hook\ConfigSchemaHooks:
    class: Drupal\custom_field_media\Hook\ConfigSchemaHooks
    autowire: true