%YAML 1.1
---
$schema: "http://stsci.edu/schemas/yaml-schema/draft-01"
id: "http://stsci.edu/schemas/asdf/core/history_entry-1.0.0"
title: |
  An entry in the file history.
description: |
  A record of an operation that has been performed
  upon a file.

type: object
properties:
  description:
    description: |
      A description of the transformation performed.
    type: string

  time:
    description: |
      A timestamp for the operation, in UTC.
    type: string
    format: date-time

  software:
    description: |
      One or more descriptions of the software that performed the
      operation.
    anyOf:
      - $ref: "software-1.0.0"
      - type: array
        items:
          $ref: "software-1.0.0"

required: [description]
additionalProperties: true
...
