curl --request GET \
  --url https://api-m.sandbox.paypal.com/v1/notifications/webhooks-lookup/{webhook_lookup_id} \
  --header 'Authorization: Bearer <token>'

{
  "id": "<string>",
  "client_id": "<string>",
  "links": [
    {
      "href": "<string>",
      "rel": "<string>"
    }
  ]
}