A position in the (created, id) keyset order that artifacts_for_resource returns rows in.It carries position and no authority: each page re-runs the read gate for the asker, so a
cursor handed to another principal, or replayed after access is revoked, reveals nothing
the read would not. That is why it is a legible object and not an opaque token, and needs
no decoder in any SDK. Every bounded artifact read continues with this one type.
{
"artifact_id": "b7bd6bbb-c7f1-4314-8742-2aeeeece9d12",
"created": "2019-08-24T14:15:22.123Z"
}