The Evil Dead 4K SteelBook: 45th Anniversary Edition (1981)

ENGLISH: DTS-HD Master Audio 5.1 (48kHz, 16-bit)
ENGLISH: DTS-HD Master Audio 2.0 (48kHz, 16-bit)
FRENCH: DTS-HD Master Audio 5.1 (48kHz, 16-bit)
GERMAN: DTS-HD Master Audio 5.1 (48kHz, 16-bit)
GERMAN: DTS-HD Master Audio 2.0 (48kHz, 16-bit)
GERMAN: DTS-HD Master Audio 2.0 (48kHz, 16-bit)
ITALIAN: DTS-HD Master Audio 5.1 (48kHz, 16-bit)
SPANISH: DTS-HD Master Audio 5.1 (48kHz, 16-bit)

• Audio Commentary - features Sam Raimi, Rob Tapert, and Bruce Campbell, and the only thing wrong with it is that it's not also available on the 4K disc.
  
• Picture-in-Picture: Join Us! The Undying Legacy of The Evil Dead - Another feature-length extra locked on Blu-ray, this one's a bit of a mystery. I couldn't find any evidence that this obviously recent extra was included on any previous domestic home video release, but it's not advertised as new on the packaging or press materials. In any case, interview snippets pop up during the film (along with text identifiers) that feature filmmaker Stuart Gordon, The Blair Witch Project's Dan Myrick, Scott "Fake Shemp" Spiegel, Alexandre Aja, and a few others gushing about The Evil Dead and its influence, and you can even chapter-skip between all of these 60-odd segments. But depending on your setup, you may have trouble with this one: my 4K player (ironically, a Sony) did not load the extra "layer" properly, but my LG Blu-ray player ran it just fine.
  
• One by One We Will Take You: The Untold Saga of The Evil Dead (53:44)
• Treasure from the Cutting Room Floor (59:22)
• At the Drive-In (12:02)
• Discovering Evil Dead (13:04)
• Make-Up Test (1:06)
• Trailer and TV Spots (5 clips, 4:00 total)