drupal/core/modules/config/config.links.task.yml

config.sync:
  route_name: config.sync
  base_route: config.sync
  title: 'Synchronize'

config.import:
  route_name: config.import_full
  title: 'Import'
  base_route: config.sync

config.export:
  route_name: config.export_full
  title: 'Export'
  base_route: config.sync

config.export_full:
  route_name: config.export_full
  title: Full archive
  parent_id: config.export

config.import_full:
  route_name: config.import_full
  title: Full archive
  parent_id: config.import

config.export_single:
  route_name: config.export_single
  title: Single item
  parent_id: config.export

config.import_single:
  route_name: config.import_single
  title: Single item
  parent_id: config.import