Swagger x-example vendor extension property

x-example.yaml

swagger: '2.0'
info:
  title: 'Form Test'
  version: '1.0'
paths:
  '/test/{param}':
    parameters:
      - name: param
        in: path
        type: number
        required: true
        x-example: 42
      - name: order
        in: query
        type: string
        x-example: asc
        default: desc
    get:
      parameters:
        - name: id
          in: formData
          type: boolean
          required: true
          x-example: false
        - name: greeting
          in: formData
          type: string
          enum:
            - hi
            - good morning
            - hello
          required: true
          x-example: hello
          default: good morning
        - name: user-agent
          in: header
          type: string
          required: true
          x-example: Examplebot/4.2 (+http://www.example.com/bot.html)
      responses:
        200:
          description: 'Success'