"-z" meaning in Old French

{
  "head_templates": [
    {
      "args": {
        "1": "fro",
        "2": "suffix"
      },
      "expansion": "-z",
      "name": "head"
    }
  ],
  "lang": "Old French",
  "lang_code": "fro",
  "pos": "suffix",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Old French entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Old French links with redundant target parameters",
          "parents": [
            "Links with redundant target parameters",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 5 entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        }
      ],
      "examples": [
        {
          "text": "mort (“dead”) (oblique singular) → morz (“dead”) (oblique plural)"
        },
        {
          "ref": "c. 1100s, Marie de France, Equitan:",
          "text": "Femme espuse ot li seneschals,\nDunt puis vient el païs granz mal[s]",
          "type": "quote"
        }
      ],
      "glosses": [
        "Replaces -ts at the end of a word."
      ],
      "id": "en--z-fro-suffix-q2i19xCv",
      "tags": [
        "morpheme"
      ]
    }
  ],
  "word": "-z"
}

{
  "head_templates": [
    {
      "args": {
        "1": "fro",
        "2": "suffix"
      },
      "expansion": "-z",
      "name": "head"
    }
  ],
  "lang": "Old French",
  "lang_code": "fro",
  "pos": "suffix",
  "senses": [
    {
      "categories": [
        "Old French entries with incorrect language header",
        "Old French lemmas",
        "Old French links with redundant target parameters",
        "Old French suffixes",
        "Old French terms with quotations",
        "Pages with 5 entries",
        "Pages with entries",
        "Quotation templates to be cleaned",
        "Requests for translations of Old French quotations"
      ],
      "examples": [
        {
          "text": "mort (“dead”) (oblique singular) → morz (“dead”) (oblique plural)"
        },
        {
          "ref": "c. 1100s, Marie de France, Equitan:",
          "text": "Femme espuse ot li seneschals,\nDunt puis vient el païs granz mal[s]",
          "type": "quote"
        }
      ],
      "glosses": [
        "Replaces -ts at the end of a word."
      ],
      "tags": [
        "morpheme"
      ]
    }
  ],
  "word": "-z"
}