This form has a randomly created ppid, but can be set by the reader.
<script>
subscriptions.linkSubscriptions({publisherProvidedId: `ppid` });
</script>
<script>
subscriptions.linkSubscriptions({linkTo: [
  { publicationId: 'pubId1', publisherProvidedId: 'ppid1' },
  { publicationId: 'pubId2', publisherProvidedId: 'ppid2' },
   …
]});
</script>
basic{
  product_id: '{publicationId}:basic',
  subscription_token: 'abc1234',
  detail: 'This is our basic plan',
  expire_time: '2025-12-01T01:59:00.139Z'
}
A successful delete returns an empty JSON object {}.
Note: this demo uses the force: true option.