The DTD files from http://hibernate.org/dtd/ have a recent timestamp (May 24 2017) but are not identical to the Git repository DTDs (eg. https://github.com/hibernate/hibernate-orm/blob/master/hibernate-core/src/main/resources/org/hibernate/hibernate-configuration-3.0.dtd )

In particular they are missing the license header which in the repository explicitly states LGPL 2.1 or later.

Git shows me the license headers have been added 2 years ago.