"known knowns" meaning in All languages combined

{
  "head_templates": [
    {
      "args": {
        "1": "en",
        "2": "noun form"
      },
      "expansion": "known knowns",
      "name": "head"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        }
      ],
      "form_of": [
        {
          "word": "known known"
        }
      ],
      "glosses": [
        "plural of known known"
      ],
      "id": "en-known_knowns-en-noun-B6ujwjr1",
      "links": [
        [
          "known known",
          "known known#English"
        ]
      ],
      "tags": [
        "form-of",
        "plural"
      ]
    }
  ],
  "word": "known knowns"
}

{
  "head_templates": [
    {
      "args": {
        "1": "en",
        "2": "noun form"
      },
      "expansion": "known knowns",
      "name": "head"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English entries with incorrect language header",
        "English non-lemma forms",
        "English noun forms",
        "Pages with 1 entry",
        "Pages with entries"
      ],
      "form_of": [
        {
          "word": "known known"
        }
      ],
      "glosses": [
        "plural of known known"
      ],
      "links": [
        [
          "known known",
          "known known#English"
        ]
      ],
      "tags": [
        "form-of",
        "plural"
      ]
    }
  ],
  "word": "known knowns"
}