json_table-1.0.6/modules/json_gridstack/json_gridstack.routing.yml

json_gridstack.block:
  path: '/json/gridstack/content/{block_id}'
  defaults:
    _title: 'Block'
    _controller: '\Drupal\json_gridstack\Controller\JsonGridstackController::showBlockContent'
    block_id: 0
  requirements:
    _permission: 'access content'