This is one of many protocol behaviors described in ActivityPub.

Identifier

urn:uuid:c67a83bd-3f47-44cc-af3a-38f176a67a18

Content

Implementations MUST NOT deliver to the "public" special collection

Origin

prefix Activities addressed to this special URI shall be accessible to all users, without authentication.

Implementations MUST NOT deliver to the "public" special collection
 
suffix ; it is not capable of receiving actual activities.

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

JSON

{
  "id": "urn:uuid:c67a83bd-3f47-44cc-af3a-38f176a67a18",
  "type": "Behavior",
  "uuid": "c67a83bd-3f47-44cc-af3a-38f176a67a18",
  "content": "Implementations MUST NOT deliver to the \"public\" special collection\n",
  "origin": {
    "source": "https://www.w3.org/TR/activitypub/",
    "section": {
      "id": "https://www.w3.org/TR/activitypub/#public-addressing",
      "branch": [
        5,
        6
      ]
    },
    "selector": {
      "type": "TextQuoteSelector",
      "prefix": "Activities addressed to this special URI shall be accessible to all users, without authentication.\n",
      "exact": "Implementations MUST NOT deliver to the \"public\" special collection\n",
      "suffix": "; it is not capable of receiving actual activities.\n"
    }
  },
  "@context": [
    "https://www.w3.org/ns/activitystreams",
    "https://socialweb.coop/ns/testing/context.json"
  ]
}