entity.entity_two.edit_form:

  path:
'/property/configuration/communication/{entity_one}/variant/{entity_two}/edit'

  defaults:

    _entity_form: communication_variant.edit
    _title: 'Add/Edit Email Variant'
    entity_one: '%id'
  options:

    parameters:
      entity_one:
        type: 'entity_one'
      communication_variant:
        type: entity:node