"-оо" meaning in Ubykh

{
  "forms": [
    {
      "form": "-oo",
      "tags": [
        "romanization"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "uby",
        "2": "suffix"
      },
      "expansion": "-оо • (-oo)",
      "name": "head"
    }
  ],
  "lang": "Ubykh",
  "lang_code": "uby",
  "pos": "suffix",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Ubykh entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "examples": [
        {
          "english": "I will kill you.",
          "roman": "Uskʷʼoo.",
          "text": "Ускәоо.",
          "type": "example"
        },
        {
          "english": "I will fade.",
          "roman": "Səcʷafadźoo.",
          "text": "Сыцәафаӡьоо.",
          "type": "example"
        }
      ],
      "glosses": [
        "suffix of future tense verbs expressing an intention"
      ],
      "id": "en--оо-uby-suffix-xwC069Ib",
      "synonyms": [
        {
          "roman": "-ow",
          "word": "-оу"
        }
      ],
      "tags": [
        "morpheme"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "[o̞ː]"
    }
  ],
  "word": "-оо"
}

{
  "forms": [
    {
      "form": "-oo",
      "tags": [
        "romanization"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "uby",
        "2": "suffix"
      },
      "expansion": "-оо • (-oo)",
      "name": "head"
    }
  ],
  "lang": "Ubykh",
  "lang_code": "uby",
  "pos": "suffix",
  "senses": [
    {
      "categories": [
        "Ubykh entries with incorrect language header",
        "Ubykh lemmas",
        "Ubykh suffixes",
        "Ubykh terms with IPA pronunciation",
        "Ubykh terms with usage examples"
      ],
      "examples": [
        {
          "english": "I will kill you.",
          "roman": "Uskʷʼoo.",
          "text": "Ускәоо.",
          "type": "example"
        },
        {
          "english": "I will fade.",
          "roman": "Səcʷafadźoo.",
          "text": "Сыцәафаӡьоо.",
          "type": "example"
        }
      ],
      "glosses": [
        "suffix of future tense verbs expressing an intention"
      ],
      "tags": [
        "morpheme"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "[o̞ː]"
    }
  ],
  "synonyms": [
    {
      "roman": "-ow",
      "word": "-оу"
    }
  ],
  "word": "-оо"
}