og_sm-8.x-1.0/og_sm.routing.yml

og_sm.site_edit:
  path: '/group/{entity_type_id}/{node}/admin/structure/site-edit'
  defaults:
    _title: 'Edit Site'
    _entity_form: 'node.edit'
  requirements:
    _entity_access: 'node.update'
  options:
    _node_operation_route: TRUE
    parameters:
      node:
        type: og_sm:site