Parse JSON LOGS à Loki, Promtail

{"level":"info","time":"2021-08-16T18:26:46.621Z","name":"bme280.data","msg":"data","temperature":26.03,"pressure":999.39,"humidity":45.32,"altitude":116}

I used following promtail config:

    scrape_configs:
    - job_name: kubernetes-pods-name
      pipeline_stages:
        - json:
            expressions:
              altitude: altitude
              humidity: humidity
              level: level
              output: msg
              pressure: pressure
              temperature: temperature
              timestamp: time
        - labels:
            level: null
        - timestamp:
            format: RFC3339
            source: timestamp
        - output:
            source: output
      kubernetes_sd_configs:
      - role: pod
      
#I was hoping that simply by defining the JSON parsing and labels I get to see these labels in the Grafana Explore. I do see the log entries in Grafana as shown below, but I don’t see any labels that are part of the JSON keys.
DreamCoder