How to get error details on response 500 api/_info/entity-schema.json?

After I activated a new plugin, I get a blank white screen after admin login. The storefront still works, no errors in the error logs. No profiler in admin, so no XDebug?

In my browser’s developer tools network tab, I see that the request to api/_info/entity-schema.json responds with a 500 Internal Server error.

But I don’t find any details about the error. No logs, no response payload, although it’s a DEV environment (Dockware).

I already checked the migration class, the entity definition, and the SQL table in adminer, where I suspect to find a subtle mismatch somewhere.

Is there any way to get more details about the error beyond the terse HTTP status message?