improvements-2.x-dev/tests/modules/improvements_test/config/schema/improvements_test.yml

improvements_test.test_config_entity.*:
  type: config_entity
  label: 'Test config entity'
  mapping:
    id:
      type: string
      label: 'ID'
    label:
      type: string
      label: 'Label'
    weight:
      type: integer
      label: 'Weight'

improvements_test.second_config_entity.*:
  type: config_entity
  label: 'Second config entity'
  mapping:
    id:
      type: string
      label: 'ID'
    label:
      type: string
      label: 'Label'