Get the description of unreleased structure that is being processed or on hold waiting for release.

{
  "rcsb_repository_holdings_prerelease": [
    {
      "entity_id": "1",
      "seq_one_letter_code": "HHHHAKQRSG..., AUCGGAAU..., (DG}(DA)(DT)(DA)(DT)...\n"
    }
  ],
  "rcsb_repository_holdings_unreleased": {
    "author_prerelease_sequence_status": "RELEASE IMMEDIATELY\n",
    "prerelease_sequence_available_flag": "Y\n",
    "status_code": "HPUB\n",
    "title": "The structure of this interesting pathogen molecule\n"
  },
  "rcsb_repository_holdings_unreleased_entry_container_identifiers": {
    "entry_id": "1KIP\n",
    "rcsb_id": "1KIP\n",
    "update_id": "2019_24\n"
  },
  "rcsb_id": "1KIP\n"
}