The official website of anime Sora no Woto has begun streaming part A of unaired episode 7.5 that is only available on DVD/Bluray volume 4.
The video is 8 minutes long and starts with Kureha writing about a lamentable occurrence that she wants to prevent from repeating by leaving a secret message. Then, she reminisces about what happened. Yumina came over to the headquarters and was invited to have lunch with others. However, she flared up and began lecturing after Kureha poured some Calvados on roasting meat. Elsewhere in the base, Kanata went to tell Rio that lunch is ready and caught her off-guard. Rio had hard time concealing the Calvados production room from Kanata who got suspicious of her. Kanata desperately wanted to know what was behind the door and Phylicia came up with an idea. If Kanata wanted to know the secret, she would have to win at a battle.
The fourth volume of Sora no Woto was released yesterday and you can get it from CDJapan
Another unaired special episode will be included in volume 7, which ships on September 22.