Suddenly  my logbook was GONE? It was not in the UI.

First troubleshooting step: check the logs and check configuration.yaml. In the configuration.yaml This contained the following code:

python_script:
  logbook:
    exclude:
      entities:
        - sensor.ha_uptime
        - sensor.ha_uptime_minutes
        - sensor.date_time

Wait, what?

If you look carefully it seems like the logbook: entry moved under the python_script: section? I have seen this happen before: where the editor (VS Code) things things need to be formatted.

NEXT: change the config so the logbook: entry moves to the top level, not under python_script.

python_script:

logbook:
  exclude:
    entities:
      - sensor.ha_uptime
      - sensor.ha_uptime_minutes
      - sensor.date_time

After a restart the logbook was not only visible but it also showed all data. One week later I have moved the empty python_script: section to a different location in the config file.

✓Fixed!