k3s/cmd/kube-aggregator/config.json

{
        "servers": [
                {
                        "serverAddress": "http://127.0.0.1:8083",
                        "groupVersionDiscoveryPaths": [
                                {
                                        "path": "/apis"
                                },
                                {
                                        "path": "/api",
                                        "isLegacy": true
                                }
                        ]
                }
        ]
}