The REST API is now versioned. For more information, see "About API versioning."
REST API endpoints for SSH signing keys
Use the REST API to manage SSH signing keys of authenticated users.
About SSH signing key administration
If a request URL does not include a {username} parameter then the response will be for the signed-in user (and you must pass authentication information with your request). Additional private information, such as whether a user has two-factor authentication enabled, is included when authenticated through OAuth with the user scope.
List SSH signing keys for the authenticated user
Lists the SSH signing keys for the authenticated user's GitHub account.
OAuth app tokens and personal access tokens (classic) need the read:ssh_signing_key scope to use this endpoint.