app.yaml: This is the main configuration file that contains information about request handlers, libraries, and other things.

index.yaml: This is automatically generated by the development server. It is required to build indexes for a datastore. We have discussed this in detail.

queue.yaml: This defines queues and the related configuration. We've covered this as well.

cron.yaml: This defines tasks that should be executed repeatedly. We'll learn about that in this chapter.

dos.yaml: This is used to blacklist certain requesting IP addresses to prevent Denial of Service attacks (DoS). You can read more about this at https://cloud.google.com/appengine/docs/python/config/dos.

dispatch.yaml: This is used with modules. We'll explore modules in this chapter and this file as well.