As you stacktrace is coming from a file build-scan.gradle.kts which is not present in the Kafka repository, I guess this is coming from some init script you have on your local disk.
For debugging “what link” it is, you probably have to set a breakpoint to the method com.gradle.enterprise.gradleplugin.internal.extension.b.link to find out.
Maybe you could post a feature request to add the label to the error message.