Both users and organizations now have the ability to request an archive of their repositories, issues, comments, and other data using the Migrations API. For more information see the developer announcement.
The node_id attribute, used to identify GraphQL API objects from the REST API, is now officially supported in the REST API v3 for GitHub.com and GitHub Enterprise (versions 2.14 and higher). The node_id attribute will be included in all supported REST resources that have a corresponding GraphQL object, and you can use this information to help move between the REST API and the GraphQL API.