"OTL" meaning in Translingual

{
  "head_templates": [
    {
      "args": {
        "1": "mul",
        "2": "symbol"
      },
      "expansion": "OTL",
      "name": "head"
    }
  ],
  "lang": "Translingual",
  "lang_code": "mul",
  "pos": "symbol",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Translingual emoticons",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Translingual entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "An emoticon representing frustration or headdesk"
      ],
      "id": "en-OTL-mul-symbol-R3Y06Lf9",
      "links": [
        [
          "emoticon",
          "emoticon#English"
        ],
        [
          "frustration",
          "frustration#English"
        ],
        [
          "headdesk",
          "headdesk#English"
        ]
      ],
      "synonyms": [
        {
          "word": "orz"
        }
      ]
    }
  ],
  "word": "OTL"
}

{
  "categories": [
    "English adjectives",
    "English countable nouns",
    "English entries with incorrect language header",
    "English lemmas",
    "English nouns",
    "English proper nouns",
    "English uncomparable adjectives"
  ],
  "head_templates": [
    {
      "args": {
        "1": "mul",
        "2": "symbol"
      },
      "expansion": "OTL",
      "name": "head"
    }
  ],
  "lang": "Translingual",
  "lang_code": "mul",
  "pos": "symbol",
  "senses": [
    {
      "categories": [
        "Translingual emoticons",
        "Translingual entries with incorrect language header",
        "Translingual lemmas",
        "Translingual symbols"
      ],
      "glosses": [
        "An emoticon representing frustration or headdesk"
      ],
      "links": [
        [
          "emoticon",
          "emoticon#English"
        ],
        [
          "frustration",
          "frustration#English"
        ],
        [
          "headdesk",
          "headdesk#English"
        ]
      ]
    }
  ],
  "synonyms": [
    {
      "word": "orz"
    }
  ],
  "word": "OTL"
}