tensorflow/core/ops/compat/ops_history_v1/Placeholder.pbtxt

op {
  name: "Placeholder"
  output_arg {
    name: "output"
    type_attr: "dtype"
  }
  attr {
    name: "dtype"
    type: "type"
  }
  attr {
    name: "shape"
    type: "shape"
    default_value {
      shape {
      }
    }
  }
}
op {
  name: "Placeholder"
  output_arg {
    name: "output"
    type_attr: "dtype"
  }
  attr {
    name: "dtype"
    type: "type"
  }
  attr {
    name: "shape"
    type: "shape"
    default_value {
      shape {
        unknown_rank: true
      }
    }
  }
}