The German Theatrical version has no optional German subtitles.
It's a Digibook. The 16 pages book is non-removable inside the case.
There is also a postcard included of the painting "Mord im Park" that plays a key role in the film.
German title: "Das Geheimnis der schwarzen Handschuhe"
Bonus DVD: -> lots of content from the Blue Underground release
Featurette "Schwarze Handschuhe" (my translation: "Black Gloves") with film historian Fabio Melelli (Italian, optional German subtitles)
Interview with Writer/Director Dario Argento "Out of the Shadow" (17:58, Italian, optional German subtitles)
Interview with Director of Photography Vittorio Storaro "Painting with Darkness" (10:03, Italian, optional German subtitles)
Interview with Composer Ennio Morricone "The Music of Murder" (7:31, Italian optional German subtitles)
Interview with Eva Renzi "Eva's talking" (11:19, Italian, optional German subtitles)
Interview with Mario Adorf "Abenteuer Filme machen - Mario Adorf erzählt..." (my english translation: The Adventure of Movie Making - Mario Adorf recounts...) (29:44, German, no subtitles)
