"Tanpopo Suisha" (Ep 13 ED) is on here. That's what drew us in.
This is sort of a surprise release, in that even I wasn't planning on it until a few hours ago. But stumbling into greatness is what got Celonius28 started to begin with, so winging it will do. Five short drama stories revolving around the cultural festival, starring Sora and friends, and concluding with the lead trio singing the full version of "Tanpopo Suisha". The final component in any Sketchbook CD collection. And yes, that Kana Hanazawa sings on it may also be partially why.
Celonius28: Hoping for a Mai Goto vs. Kana Hanazawa Battle of the Imoutos.