This is one of many protocol behaviors described in ActivityPub.

Identifier

urn:uuid:f3725db1-1e6b-4d20-9cea-a49ef4291e9f

Content

Any to, bto, cc, bcc, and audience properties specified on the object MUST be copied over to the new Create activity by the server.

Origin

prefix The Location value returned by the server should be the URL of the new Create activity (rather than the object).

Any to, bto, cc, bcc, and audience properties specified on the object MUST be copied over to the new Create activity by the server.
 
suffix Example 15: Object with audience targeting

https://www.w3.org/TR/activitypub/

JSON

{
  "id": "urn:uuid:f3725db1-1e6b-4d20-9cea-a49ef4291e9f",
  "uuid": "f3725db1-1e6b-4d20-9cea-a49ef4291e9f",
  "type": "Behavior",
  "content": "Any to, bto, cc, bcc, and audience properties specified on the object MUST be copied over to the new Create activity by the server.\n",
  "context": [
    "https://www.w3.org/TR/activitypub/",
    {
      "name": "6.2 Create Activity",
      "id": "https://www.w3.org/TR/activitypub/#create-activity-outbox"
    },
    {
      "name": "6.2.1 Object creation without a Create Activity",
      "id": "https://www.w3.org/TR/activitypub/#object-without-create"
    }
  ],
  "origin": {
    "source": "https://www.w3.org/TR/activitypub/",
    "section": {
      "id": "https://www.w3.org/TR/activitypub/#object-without-create",
      "name": "Object creation without a Create Activity",
      "branch": [
        6,
        2,
        1
      ]
    },
    "selector": {
      "type": "TextQuoteSelector",
      "prefix": "The Location value returned by the server should be the URL of the new Create activity (rather than the object). \n",
      "exact": "Any to, bto, cc, bcc, and audience properties specified on the object MUST be copied over to the new Create activity by the server.\n",
      "suffix": "Example 15: Object with audience targeting\n"
    }
  },
  "@context": [
    "https://www.w3.org/ns/activitystreams",
    "https://socialweb.coop/ns/testing/context.json"
  ]
}