The Hobbit Blu-ray Extended Editions feature extensive documentary material called "Appendices". These appendices are detailed behind-the-scenes documentaries that delve into the creation of the films, including casting, set design, visual effects, and more. They are often more extensive than the films themselves, providing a comprehensive look at the filmmaking process.
Part Seven: A Long-Expected Journey: The Chronicles of The Hobbit – Part 1, focuses on the production effort of assembling the crew, casting, pre-production, the actual filming and so forth.
Part Eight: Return to Middle-Earth, is broken into sections that look more specifically at all of the elaborate design and visual effects work that went into the film.
Part Nine: Into the Wilderland: The Chronicles of The Hobbit – Part 2. Following in the pattern of the previous discs, this material is much more focused on the nuances of the production design for the film’s new characters and settings, and also its post-production.
Part Ten: The Journey to Erebor. Following in the pattern of the previous discs, this material is much more focused on the nuances of the production design for the film’s new characters and settings, and also its post-production.
Part Eleven: The Gathering Storm. All of the content on this disc forms what is essentially a nearly 5-hour long behind-the-scenes documentary of the filming. The documentary comes in 10 parts.
Part Twelve: Here at Journey’s End. This offers another 5 hours worth of video bonus material in the form of four mini-documentaries.