Long ago, when Subversion first learned to store versioned data, it did so using a storage layer implementation based on the Berkeley DB (BDB) transactional database system. As the product matured, though, this storage layer implementation was joined by—and then outmatched by—another one, the FSFS backend which is used by the vast majority of Subversion's repositories today. In Subversion 1.8, the Subversion development community announced that the BDB-based storage layer was being officially deprecated.
This appendix presents some of the documentation about administering BDB-backed repositories featured more prominently in previous versions of this book.
 Okay, strictly speaking, it used XML files for starters. But that was never intended for public release.