You are using the GData feed, rendered in JSON. There is nothing illegal here, just an older rendering. I think the newer JSON format rendered off of googleapis.com/blogger/* is an easier to use. The GData feeds will be supported for the foreseeable future, but future additions will be made on the Blogger JSON API base, as it has newer client library support, and internal infrastructure support.
Is there something in the GData feed that you need that isn't in the Blogger JSON API?