Notification variables not documented

I’m not sure where the best place to post this is, but, the usage of the notification.* variables do not appear to be documented anywhere on the Variables page or at all.

Although I could guess what they do, adding them to the proper doc page and table would be useful. For example: what are “changes” compared to “body” and what does an example output look like? I am working on custom Triggers for Webhooks, but these ones specifically are a bit of a mystery, and where I would use them.

List of mentioned variables:

Example of how I’m currently sorta using them for Pushover notifications:

{
  "token": "#{ticket.owner.pushover_api_key}",
  "user": "#{ticket.owner.pushover_user_key}",
  "title": "#{notification.subject} [#{config.ticket_hook}#{ticket.number}]",
  "message": "#{notification.message}\n\nChanges:\n#{notification.changes}\n\n#{notification.body}",
  "url": "#{notification.link}",
  "url_title": "#{config.ticket_hook}#{ticket.number}"
}

Thanks!