mkdocs-material/docs/schema/nav.json

{
  "$schema": "https://json-schema.org/draft-07/schema",
  "title": "Navigation tree",
  "markdownDescription": "https://www.mkdocs.org/user-guide/configuration/#nav",
  "type": "array",
  "items": {
    "anyOf": [
      {
        "title": "Navigation item",
        "markdownDescription": "https://www.mkdocs.org/user-guide/configuration/#nav",
        "pattern": "\\.md$"
      },
      {
        "type": "object",
        "markdownDescription": "https://www.mkdocs.org/user-guide/configuration/#nav",
        "patternProperties": {
          ".*": {
            "oneOf": [
              {
                "title": "Navigation item",
                "markdownDescription": "https://www.mkdocs.org/user-guide/configuration/#nav",
                "pattern": "\\.md$"
              },
              {
                "$ref": "#"
              }
            ]
          }
        }
      }
    ]
  },
  "additionalItems": false
}