Which index do elastic agents output too?

I'm trying to configure a stand alone elastic agent. I get a success response during installation but i'm not sure which index in elasticsearch the data get sent to? This is my elastic-agent.yml file:

    type: elasticsearch
    hosts: ["elastic.example.net:9200"]
    username: "elastic"
    password: "HELLO9999"
  - type: system/metrics
    id: unique-system-metrics-input
    data_stream.namespace: default
    use_output: default
      - metricset: cpu
        data_stream.dataset: system.cpu
      - metricset: memory
        data_stream.dataset: system.memory
      - metricset: network
        data_stream.dataset: system.network
      - metricset: filesystem
        data_stream.dataset: system.filesystem
agent.logging.to_stderr: true

Then I typed ./elastic-agent.exe install. I said no to the fleet server. After a few seconds, I get the message Elastic Agent has been successfully installed. So which index do I look in to see my data?

Well agents output to data streams not indices directly.

Data streams are backed by indices.

Perhaps you should read about data streams a bit.

If you go to the Kibana - Stack Management - Index Management - Data Streams

And search for system you should probably see the system metrics data stream in the default namespace.