?compress (efficient document)

[cubap]

{  "label": "Sample Data",
   "forCollection": {
       "value": "Sample Collection"
    },
   "date": 123093091209,
   "seeAlso": {
      "@id": "https://example.com/42",
      "label": { "en": "external resource", "none":"externalatio"},
   },
   "__rerum": { ... }
}

Becomes...

{  "label": "Sample Data",
   "forCollection": {
       "value": "Sample Collection"
    },
   "date": 123093091209,
   "seeAlso": {
      "@id": "https://example.com/42",
      "label": { "en": "external resource", "none":"externalatio"},
   }
}

Compare to compact which will promote value and @id properties with prejudice.