openapi: 3.0.0
info:
  title: foo
  version: 0.0.0
paths:
  /{external1}:
    parameters:
      - in: path
        name: external1
        required: true
        schema:
          $ref: './components.yml#/components/schemas/External1'
    get:
      responses:
        '204':
          description: No content