curl --request GET \
  --url https://api.planetscale.com/v1/organizations/{organization}/databases/{database}/branches/{branch}/backups/{id} \
  --header 'Authorization: <api-key>'

{
  "id": "<string>",
  "name": "<string>",
  "state": "pending",
  "size": 123,
  "estimated_storage_cost": 123,
  "created_at": "<string>",
  "updated_at": "<string>",
  "started_at": "<string>",
  "expires_at": "<string>",
  "completed_at": "<string>",
  "deleted_at": "<string>",
  "pvc_size": 123,
  "protected": true,
  "required": true,
  "restored_branches": [
    {}
  ],
  "actor": {},
  "backup_policy": {},
  "schema_snapshot": {},
  "database_branch": {}
}