Search Index has a method to delete a document. https://cloud.google.com/appengine/docs/standard/python/search/indexclass (Python) https://cloud.google.com/appengine/docs/standard/java/javadoc/com/google/appengine/api/search/Index (java)
But how to delete Index itself?
Empty Index was listed at the Text Search Panel in the Admin Console.
but no button to delete.