json-schema-validator/test/issue-143/schema.json

{
    "type": "object",

    "properties": {
        "unknown_keyword_storage": {
            "1": {
                "type": "number"
            },
            "a": {
                "type": "string"
            }
        },
        "ref1": {
            "$ref": "#/properties/unknown_keyword_storage/1"
        },
        "refa": {
            "$ref": "#/properties/unknown_keyword_storage/a"
        }
    },
    "additionalProperties": false
}