Checklist

• I have updated to the latest available Home Assistant version.
• I have cleared the cache of my browser.
• I have tried a different browser to see if it is related to my browser.
• I have tried reproducing the issue in safe mode to rule out problems with unsupported custom resources.

Describe the issue you are experiencing

Since the UI redesign, the exact error messages thrown by card setConfig are missing:

This legacy error message should have been shown:

    if (
      !config.show_all &&
      !config.entities?.length &&
      !config.geo_location_sources
    ) {
      throw new Error(
        "Either show_all, entities, or geo_location_sources must be specified"
      );
    }

Describe the behavior you expected

Show the reason for the configuration error.

Steps to reproduce the issue

1. as above

...

What version of Home Assistant Core has the issue?

2025.6.b0

What was the last working version of Home Assistant Core?

No response

In which browser are you experiencing the issue?

No response

Which operating system are you using to run this browser?

No response

State of relevant entities

Problem-relevant frontend configuration

Javascript errors shown in your browser console/inspector

Additional information

No response