docs/data/reusables/webhooks/issue_properties.md

issue|object | The issue itself. changes|object| The changes to the issue if the action was edited. changes[title][from]|string | The previous version of the title if the action was edited. changes[body][from]|string | The previous version of the body if the action was edited. assignee|object | The optional user who was assigned or unassigned from the issue. label|object | The optional label that was added or removed from the issue.