"+0" meaning in English

{
  "etymology_text": "From Internet decision-making processes such as Apache that allow users to vote for or against a proposal, or signaling slight agreement or disagreement. E.g., http://httpd.apache.org/dev/guidelines.html.",
  "head_templates": [
    {
      "args": {
        "1": "en",
        "2": "interjection",
        "head": "+0"
      },
      "expansion": "+0",
      "name": "head"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "intj",
  "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"
        }
      ],
      "glosses": [
        "Used to signify assent to a proposal without indicating a strong opinion."
      ],
      "id": "en-+0-en-intj-i4TsrRQE",
      "links": [
        [
          "Internet",
          "Internet"
        ],
        [
          "slang",
          "slang"
        ]
      ],
      "raw_glosses": [
        "(Internet slang) Used to signify assent to a proposal without indicating a strong opinion."
      ],
      "related": [
        {
          "word": "+1"
        }
      ],
      "tags": [
        "Internet"
      ]
    }
  ],
  "word": "+0"
}

{
  "etymology_text": "From Internet decision-making processes such as Apache that allow users to vote for or against a proposal, or signaling slight agreement or disagreement. E.g., http://httpd.apache.org/dev/guidelines.html.",
  "head_templates": [
    {
      "args": {
        "1": "en",
        "2": "interjection",
        "head": "+0"
      },
      "expansion": "+0",
      "name": "head"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "intj",
  "related": [
    {
      "word": "+1"
    }
  ],
  "senses": [
    {
      "categories": [
        "English entries with incorrect language header",
        "English interjections",
        "English internet slang",
        "English lemmas",
        "English terms spelled with +",
        "English terms spelled with numbers",
        "Pages with 1 entry",
        "Pages with entries"
      ],
      "glosses": [
        "Used to signify assent to a proposal without indicating a strong opinion."
      ],
      "links": [
        [
          "Internet",
          "Internet"
        ],
        [
          "slang",
          "slang"
        ]
      ],
      "raw_glosses": [
        "(Internet slang) Used to signify assent to a proposal without indicating a strong opinion."
      ],
      "tags": [
        "Internet"
      ]
    }
  ],
  "word": "+0"
}